//#include <iostream>
#include <vector>
#include <fstream>
//#include <stdlib.h>

using namespace std;
int n,nrop;
int nivel[100000];
int log2[200000];
int primaaparitie[100100];
vector <int> euler;
vector <int> arbore[100100];
vector <vector <int> > RMQ;
ifstream in("lca.in");
ofstream out("lca.out");



int nivel_min(int a,int b)
{
    if(nivel[a]<nivel[b])return a;
    return b;
}



int putere_2(int n,int x=1)
{
    if(n==0)return x;
    else return putere_2(n-1,x<<1);
}
void generare_euler(int n)
{
    primaaparitie[n]=euler.size();
    euler.push_back(n);
    vector <int> forRMQ;
    RMQ.push_back(forRMQ);
    if(arbore[n].size()>0)
    {
        for(unsigned int i=0; i<arbore[n].size(); i++)
        {
            generare_euler(arbore[n][i]);
            euler.push_back(n);
            RMQ.push_back(forRMQ);
        }
    }
}


void rmq()
{
    for(unsigned int i=0; i<euler.size(); i++)
    {
        RMQ[i].push_back(euler[i]);
    }
    for(unsigned int i=1; putere_2(i)<euler.size(); i++)
    {
        for(unsigned int j=0; putere_2(i)+j<euler.size(); j++)
        {
            RMQ[j].push_back(nivel_min(RMQ[j][i-1],RMQ[j+putere_2(i-1)][i-1]));
        }
    }
}

void logaritmare()
{
    for(int i=2; i<=2*n; i++)log2[i]=log2[i/2]+1;


}


int calcul_minim(int a,int b)
{
    int diferenta=b-a+1;
    int pow=log2[diferenta];
    int rest=diferenta-(1<<pow);
    return nivel_min(RMQ[a][pow],RMQ[a+rest][pow]);

}

int main()
{
    log2[1]=0;
    nivel[0]=0;
    in>>n>>nrop;

    logaritmare();
    int x;


    for(int i=1; i<n; i++)
    {
        in>>x;
        arbore[x-1].push_back(i);
        nivel[i]=nivel[x-1]+1;

    }
    generare_euler(0);
    rmq();
    for(int i=0; i<nrop; i++)
    {
        int a,b;
        in>>a>>b;
        a--;b--;
        if(primaaparitie[a]>primaaparitie[b])
    {
        a=a^b;
        b=a^b;
        a=a^b;
    }
    out<<calcul_minim(primaaparitie[a],primaaparitie[b])+1<<endl;

    }

    return 0;
}