#include<bits/stdc++.h>
using namespace std;
ifstream fin("lca.in");
ofstream fout("lca.out");
int const N = 2e5 + 3 , L = 20;
int n , m , sz , a , b;
int t[N] , d[N] , idx[N] , eu[N] , Log2[N];
int dp[N][L];
vector<int> v[N];
bitset<N> viz;
void dfs(int x){
    viz[x] = 1;
    d[x] = 1 + d[t[x]];
    if(!idx[x])
        idx[x] = ++sz;
    eu[sz] = x;
    for(auto y : v[x]){
        if(viz[y])
            continue;
        dfs(y);
        eu[++ sz] = x;
    }
}
int Min(int a , int b){
    return (d[a] < d[b] ? a : b);
}
int main(){
    fin >> n >> m;
    for(int i = 2 ; i <= n ; ++ i){
        fin >> t[i];
        v[t[i]].push_back(i);
        v[i].push_back(t[i]);
    }
    dfs(1);
    for(int j = 0 ; (1 << j) <= sz ; ++ j){
        for(int i = (1 << j) ; i <= sz ; ++ i){
            if(!j)
                dp[i][j] = eu[i];
            else
                dp[i][j] = Min(dp[i][j - 1] , dp[i - (1 << (j - 1))][j - 1]);
        }
    }
    for(int i = 2 ; i < N ; ++ i)
        Log2[i] = 1 + Log2[i >> 1];
    for(int i = 1 ; i <= m ; ++ i){
        fin >> a >> b;
        a = idx[a] , b = idx[b];
        if(a > b)
            swap(a , b);
        int l = Log2[b - a + 1];
        fout << Min(dp[b][l] , dp[a + (1 << l) - 1][l]) << '\n';
    }
    return 0;
}