#include <bits/stdc++.h>
#define MAX 100005
#define NMAX 400100
using namespace std;

ifstream in("lca.in");
ofstream out("lca.out");

struct ex{
    int e, nivel;
}v[MAX];

int n, m, t[MAX], r, z, poz, val, x, y, minim, pozminim;

map < int , int > hashis;
bitset < MAX > c;
stack < int > st;


void Euler(int k){
    st.push(k);
    v[++z].e = k;
    v[z].nivel = st.size() - 1;
    if(!hashis[k])
        hashis[k] = z;
    c[k] = true;
    for(int i = 1; i <= n; i++)
        if(!c[i] && t[i] == k)
            Euler(i);
    st.pop();
    if(t[k]){
        v[++z].e = t[k];
        v[z].nivel = st.size() - 1;
    }
}

int main(){
    in>>n>>m;
    for(int i = 2; i <= n; i++)
        in>>t[i];
    Euler(1);
    for(int i = 1; i <= z; i++){
        poz = i, val = v[i].nivel;
    }
    Euler(1);

    while(m){
        in>>x>>y;
        x = hashis[x], y = hashis[y];
        if(x > y)
            x ^= y, y ^= x, x ^= y;
        minim = (1 << 30), pozminim = 0;
        for(int i = x; i <= y; i++){
            if(minim > v[i].nivel)
                minim = v[i].nivel, pozminim = i;
        }
        out<<v[pozminim].e<<"\n";
        m--;
    }
}