#line 1 "graph_tree/test/LC_lca.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/lca"
#line 2 "graph_tree/lca.hpp"
#include<vector>
#include<cmath>
#include<tuple>
#line 4 "graph_tree/graph_template.hpp"
#include<iostream>
/**
* @brief グラフテンプレート
*/
using graph=std::vector<std::vector<int>>;
template<typename T>
using graph_w=std::vector<std::vector<std::pair<int,T>>>;
graph load_graph(int n,int m){graph g(n);for(int i=0;i<m;++i){int s,t;std::cin>>s>>t;--s;--t;g[s].push_back(t);g[t].push_back(s);}return g;}
graph load_digraph(int n,int m){graph g(n);for(int i=0;i<m;++i){int s,t;std::cin>>s>>t;--s;--t;g[s].push_back(t);}return g;}
graph load_graph0(int n,int m){graph g(n);for(int i=0;i<m;++i){int s,t;std::cin>>s>>t;g[s].push_back(t);g[t].push_back(s);}return g;}
graph load_digraph0(int n,int m){graph g(n);for(int i=0;i<m;++i){int s,t;std::cin>>s>>t;g[s].push_back(t);}return g;}
graph load_tree(int n){graph g(n);for(int i=0;i<n-1;++i){int s,t;std::cin>>s>>t;--s;--t;g[s].push_back(t);g[t].push_back(s);}return g;}
graph load_tree0(int n){graph g(n);for(int i=0;i<n-1;++i){int s,t;std::cin>>s>>t;g[s].push_back(t);g[t].push_back(s);}return g;}
graph load_treep(int n){graph g(n);for(int i=0;i<n-1;++i){int t;std::cin>>t;g[i+1].push_back(t);g[t].push_back(i+1);}return g;}
template<typename T>graph_w<T> load_graph_weight(int n,int m){graph_w<T> g(n);for(int i=0;i<m;++i){int s,t;T u;std::cin>>s>>t>>u;--s;--t;g[s].emplace_back(t,u);g[t].emplace_back(s,u);}return g;}
template<typename T>graph_w<T> load_digraph_weight(int n,int m){graph_w<T> g(n);for(int i=0;i<m;++i){int s,t;T u;std::cin>>s>>t>>u;--s;--t;g[s].emplace_back(t,u);}return g;}
template<typename T>graph_w<T> load_graph0_weight(int n,int m){graph_w<T> g(n);for(int i=0;i<m;++i){int s,t;T u;std::cin>>s>>t>>u;g[s].emplace_back(t,u);g[t].emplace_back(s,u);}return g;}
template<typename T>graph_w<T> load_digraph0_weight(int n,int m){graph_w<T> g(n);for(int i=0;i<m;++i){int s,t;T u;std::cin>>s>>t>>u;g[s].emplace_back(t,u);}return g;}
template<typename T>graph_w<T> load_tree_weight(int n){graph_w<T> g(n);for(int i=0;i<n-1;++i){int s,t;T u;std::cin>>s>>t>>u;--s;--t;g[s].emplace_back(t,u);g[t].emplace_back(s,u);}return g;}
template<typename T>graph_w<T> load_tree0_weight(int n){graph_w<T> g(n);for(int i=0;i<n-1;++i){int s,t;T u;std::cin>>s>>t>>u;g[s].emplace_back(t,u);g[t].emplace_back(s,u);}return g;}
template<typename T>graph_w<T> load_treep_weight(int n){graph_w<T> g(n);for(int i=0;i<n-1;++i){int t;T u;std::cin>>t>>u;g[i+1].emplace_back(t,u);g[t].emplace_back(i+1,u);}return g;}
#line 5 "graph_tree/depth.hpp"
/**
* @brief 根からの深さ
*/
std::vector<int> depth(const graph& g,int start){
std::vector<int>memo(g.size());
auto f=[&](auto f,int v,int p)->int{
int mx=0;
for(auto t:g[v]){
if(t==p)continue;
mx=std::max(mx,f(f,t,v));
}
return memo[v]=mx+1;
};
f(f,start,-1);
return memo;
}
#line 1 "graph_tree/distance.hpp"
std::vector<int> distance(const graph& G,int start){
std::vector<int>memo(G.size());
auto f=[&](auto f,int v,int p,int i)->void{
for(auto t:G[v]){
if(t==p)continue;
f(f,t,v,i+1);
}
memo[v]=i;
};
f(f,start,-1,0);
return memo;
}
#line 2 "data_structure/arg_rmq.hpp"
#include<assert.h>
#line 4 "data_structure/arg_rmq.hpp"
#include<stack>
#include<numeric>
#line 7 "data_structure/arg_rmq.hpp"
#include<algorithm>
#line 3 "data_structure/small_rmq.hpp"
/**
* RMQ(small) &lt;O(N),O(1)&gt;(N<=64)
*/
template<typename T>
class small_rmq{
using u64=unsigned long long;
std::vector<u64>table;
std::vector<T> v;
public:
small_rmq(std::vector<T> v):v(v){
assert(v.size()<=64);
std::vector<int>tmp(v.size());
table.resize(v.size(),0);
std::stack<T>stk;
for(int i=0;i<(int)v.size();++i){
tmp.resize(v.size());
while(!stk.empty()&&v[stk.top()]>=v[i]){
stk.pop();
}
tmp[i]=stk.empty()?-1:stk.top();
stk.emplace(i);
}
for(int i=0;i<(int)v.size();++i){
if(tmp[i]!=-1)table[i]=table[tmp[i]]|(1ULL<<(tmp[i]));
}
}
T query(int l,int r){
assert(l!=r);
const u64 tmp=table[r-1]&~((1ULL<<l)-1);
if(tmp==0)return r-1;
else return __builtin_ctzll(tmp);
}
};
#line 3 "data_structure/sparse_table.hpp"
#include<functional>
#line 2 "alga/maybe.hpp"
#include<cassert>
/**
* @brief Maybe
* @see https://ja.wikipedia.org/wiki/%E3%83%A2%E3%83%8A%E3%83%89_(%E3%83%97%E3%83%AD%E3%82%B0%E3%83%A9%E3%83%9F%E3%83%B3%E3%82%B0)#Maybe%E3%83%A2%E3%83%8A%E3%83%89
*/
template<typename T>
struct maybe{
bool _is_none;
T val;
maybe():_is_none(true){}
maybe(T val):_is_none(false),val(val){}
T unwrap()const{
assert(!_is_none);
return val;
}
T unwrap_or(T e)const{
return _is_none?e:val;
}
bool is_none()const{return _is_none;}
bool is_some()const{return !_is_none;}
};
template<typename T,typename F>
auto expand(F op){
return [&op](const maybe<T>& s,const maybe<T>& t){
if(s.is_none())return t;
if(t.is_none())return s;
return maybe<T>(op(s.unwrap(),t.unwrap()));
};
}
#line 7 "data_structure/sparse_table.hpp"
/**
* @brief SparseTable
*/
template<typename T,typename F>
class sparse_table{
F f;
std::vector<std::vector<T>>data;
public:
sparse_table(std::vector<T> v,F f=F()):f(f){
int n=v.size(),log=log2(n)+1;
data.resize(n,std::vector<T>(log));
for(int i=0;i<n;i++)data[i][0]=v[i];
for(int j=1;j<log;j++)for(int i=0;i+(1<<(j-1))<n;i++){
data[i][j]=f(data[i][j-1],data[i+(1<<(j-1))][j-1]);
}
}
maybe<T> get(int l,int r){
if(l==r)return maybe<T>();
if(r<l)std::swap(l,r);
int k=std::log2(r-l);
return maybe<T>(f(data[l][k],data[r-(1<<k)][k]));
}
};
#line 3 "functional/argmin.hpp"
/**
* @brief 最小値とその位置
*/
template<typename T,typename E>
struct argmin{
std::pair<T,E> operator()(const std::pair<T,E>& s,const std::pair<T,E>& t){
return s.second<=t.second?s:t;
}
};
#line 11 "data_structure/arg_rmq.hpp"
/**
* @brief RangeArgminQuery &lt;O(N),O(1)&gt;
* @see https://noshi91.hatenablog.com/entry/2018/08/16/125415
*/
template<typename T>
class arg_rmq{
constexpr static int b=64;
std::vector<T>v;
std::vector<small_rmq<T>*>backet;
sparse_table<std::pair<int,T>,argmin<int,T>>* st=0;
public:
arg_rmq(std::vector<T>v):v(v){
std::vector<std::pair<int,T>>tmp2;
for(int i=0;i<(int)v.size();i+=b){
std::vector<T>tmp;
T mn=std::numeric_limits<T>::max();
int idx=-1;
for(int j=0;i+j<(int)v.size()&&j<b;j++){
tmp.push_back(v[i+j]);
if(mn>v[i+j]){
mn=v[i+j];
idx=i+j;
}
}
tmp2.emplace_back(idx,mn);
backet.push_back(new small_rmq<T>(tmp));
}
st=new sparse_table<std::pair<int,T>,argmin<int,T>>(tmp2);
}
maybe<std::pair<int,T>> query(int s,int t){
if(s==t)return maybe<std::pair<int,T>>();
if(s/b==t/b){
int idx=s/b*b+backet[s/b]->query(s%b,t%b);
return maybe<std::pair<int,T>>(std::make_pair(idx,v[idx]));
}
std::pair<int,T> res=std::make_pair(-1,std::numeric_limits<T>::max());
{
int idx=s/b*b+backet[s/b]->query(s%b,b);
res=argmin<int,T>()(res,std::make_pair(idx,v[idx]));
}
if(s/b+1!=t/b)res=argmin<int,T>()(res,st->get(s/b+1,t/b).unwrap());
if(t%b!=0){
int idx=t/b*b+backet[t/b]->query(0,t%b);
res=argmin<int,T>()(res,std::make_pair(idx,v[idx]));
}
return maybe<std::pair<int,T>>(res);
}
};
#line 9 "graph_tree/lca.hpp"
/**
* @brief LCA &lt;O(N),O(1)&gt;(HL分解と同等の速さ)
*/
class lca{
std::vector<int>data;
std::vector<int>comp_data;
std::vector<int>start;
arg_rmq<int>*st;
std::vector<int> __dist;
public:
lca(){}
lca(std::vector<std::vector<int>>v,int s){
data.resize(v.size()*2-1);
comp_data.resize(v.size()*2-1);
start.resize(v.size());
int i=0;
__dist=distance(v,s);
auto f=[&](auto f,int n,int p)->void{
start[n]=i;
data[i]=n;
comp_data[i++]=__dist[n];
for(int t:v[n]){
if(t==p)continue;
f(f,t,n);
data[i]=n;
comp_data[i++]=__dist[n];
}
};
f(f,s,-1);
st=new arg_rmq<int>(comp_data);
}
int query(int p,int q){
return data[st->query(std::min(start[p],start[q]),std::max(start[p],start[q])+1).unwrap().first];
}
int dist(int p,int q){
return __dist[p]+__dist[q]-2*__dist[query(p,q)];
}
};
#line 2 "util/template.hpp"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")
#include<bits/stdc++.h>
using namespace std;
struct __INIT__{__INIT__(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}}__INIT__;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define endl ('\n')
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>using V=vector<T>;
template<typename T>using VV=V<V<T>>;
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void debug(T t){bool f=0;for(auto i:t){cerr<<(f?" ":"")<<i;f=1;}cerr<<endl;}
template<typename T>inline void debug2(T t){for(auto i:t)output(i);}
#define loop(n) for(long long _=0;_<(long long)(n);++_)
#define _overload4(_1,_2,_3,_4,name,...) name
#define __rep(i,a) repi(i,0,a,1)
#define _rep(i,a,b) repi(i,a,b,1)
#define repi(i,a,b,c) for(long long i=(long long)(a);i<(long long)(b);i+=c)
#define rep(...) _overload4(__VA_ARGS__,repi,_rep,__rep)(__VA_ARGS__)
#define _overload3_rev(_1,_2,_3,name,...) name
#define _rep_rev(i,a) repi_rev(i,0,a)
#define repi_rev(i,a,b) for(long long i=(long long)(b)-1;i>=(long long)(a);--i)
#define rrep(...) _overload3_rev(__VA_ARGS__,repi_rev,_rep_rev)(__VA_ARGS__)
// #define rep(i,...) for(auto i:range(__VA_ARGS__))
// #define rrep(i,...) for(auto i:reversed(range(__VA_ARGS__)))
// #define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
// #define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
// #define irep(i) for(lint i=0;;++i)
// inline vector<long long> range(long long n){if(n<=0)return vector<long long>();vector<long long>v(n);iota(v.begin(),v.end(),0LL);return v;}
// inline vector<long long> range(long long a,long long b){if(b<=a)return vector<long long>();vector<long long>v(b-a);iota(v.begin(),v.end(),a);return v;}
// inline vector<long long> range(long long a,long long b,long long c){if((b-a+c-1)/c<=0)return vector<long long>();vector<long long>v((b-a+c-1)/c);for(int i=0;i<(int)v.size();++i)v[i]=i?v[i-1]+c:a;return v;}
// template<typename T>inline T reversed(T v){reverse(v.begin(),v.end());return v;}
#define all(n) begin(n),end(n)
template<typename T,typename E>bool chmin(T& s,const E& t){bool res=s>t;s=min<T>(s,t);return res;}
template<typename T,typename E>bool chmax(T& s,const E& t){bool res=s<t;s=max<T>(s,t);return res;}
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
template<typename T,typename ...Args>auto make_vector(T x,int arg,Args ...args){if constexpr(sizeof...(args)==0)return vector<T>(arg,x);else return vector(arg,make_vector<T>(x,args...));}
#define extrep(v,...) for(auto v:__MAKE_MAT__({__VA_ARGS__}))
#define bit(n,a) ((n>>a)&1)
vector<vector<long long>> __MAKE_MAT__(vector<long long> v){if(v.empty())return vector<vector<long long>>(1,vector<long long>());long long n=v.back();v.pop_back();vector<vector<long long>> ret;vector<vector<long long>> tmp=__MAKE_MAT__(v);for(auto e:tmp)for(long long i=0;i<n;++i){ret.push_back(e);ret.back().push_back(i);}return ret;}
using graph=vector<vector<int>>;
template<typename T>using graph_w=vector<vector<pair<int,T>>>;
template<typename T,typename E>ostream& operator<<(ostream& out,pair<T,E>v){out<<"("<<v.first<<","<<v.second<<")";return out;}
constexpr inline long long powll(long long a,long long b){long long res=1;while(b--)res*=a;return res;}
#line 4 "graph_tree/test/LC_lca.test.cpp"
int main(){
lint n,q;
cin>>n>>q;
auto g=load_treep(n);
lca lca(g,0);
while(q--){
lint s,t;
cin>>s>>t;
cout<<lca.query(s,t)<<endl;
}
}
graph_tree/test/LC_lca.test.cpp