#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>

using namespace std;

#define MAX 100008

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

typedef vector < int > ::iterator iter;
vector < int > g[MAX];
int b[2*MAX-1],lev[2*MAX-1],r[17][MAX],pos[MAX],n,m,k;

void df(int nod, int niv)
{
    b[++k]=nod;
    pos[nod]=k;
    lev[nod]=niv;
    for(iter it=g[nod].begin();it!=g[nod].end();it++)
    {
        df(*it,niv+1);
        b[++k]=nod;
    }
}

void rmq()
{
    for(int i=1;i<=k;i++)
        r[0][i]=b[i];
    for(int i=1;(1<<i)<=k;i++)
        for(int j=1;j<=k-(1<<i)+1;j++)
        {
            if(lev[r[i-1][j]] < lev[r[i-1][j+(1<<(i-1))]])
                r[i][j] = r[i-1][j];
            else
                r[i][j] = r[i-1][j+(1<<(i-1))];
        }
}

int main()
{
    fin>>n>>m;
    for(int i=2; i<=n; i++)
    {
        int x;
        fin>>x;
        g[x].push_back(i);
    }
    df(1,0);
    rmq();
    while(m--)
    {
        int x,y,start,stop;
        fin>>x>>y;
        start = pos[x];
        stop = pos[y];
        if(stop < start)
            swap(start, stop);
        int h = log2(stop-start+1);
        int l=min(r[h][start], r[h][stop+1-(1<<h)]);
        fout<<l<<"\n";
    }
    fin.close();
    fout.close();
    return 0;
}