#include <bits/stdc++.h>
using namespace std;
ifstream f("lca.in");
ofstream g("lca.out");
struct elem
{
    int nod, niv;
};
int nivel[300009];
vector <int> v[300009];
elem rmq[22][300009];
int tata[300009], lin[300009], poz[300009], ap[300009];
int cnt=0;
elem mini (elem x, elem y)
{
    if (x.niv<=y.niv)
        return x;
    return y;
}
void dfs (int nod)
{
    lin[++cnt]=nod;
    if (!poz[nod]) poz[nod]=cnt;
    rmq[0][cnt]={nod, nivel[nod]};
    for (auto y:v[nod])
    {
        nivel[y]=nivel[nod]+1;
        dfs (y);
        lin[++cnt]=nod;
        rmq[0][cnt]={nod, nivel[nod]};
    }
}
int p[22];
elem query (int x, int y)
{
    int st=poz[x], dr=poz[y];
    if (st>dr)
        swap (st, dr);
    int lungime=dr-st+1;
    int lg=ap[lungime];

    //cout << lg << ' ';
    return mini (rmq[lg][st], rmq[lg][dr-p[lg]+1]);
}
signed main ()
{
    int n, m;
    f >> n >> m;
    for (int i=2; i<=n; i++)
    {
        f >> tata[i];
        v[tata[i]].push_back(i);
    }
    dfs (1);
    p[0]=1;
    for (int i=1; i<=20; i++)
        p[i]=2*p[i-1];
    for (int i=1; p[i]<=cnt; i++)
    {
        //cout << i << ' ' ;
        for (int j=1; j+p[i]-1<=cnt; j++)
        {
            rmq[i][j]=mini (rmq[i-1][j], rmq[i-1][j+p[i-1]]);
        }
    }
    int val=1, curr=0;
    for (int i=2; i<=cnt; i++)
    {
        while (2*val<=i)
        {
            curr++;
            val*=2;
        }
        ap[i]=curr;
    }
    //cout<<nivel[5]<<' ';
    while (m--)
    {
        int x, y;
        f >> x >> y;
        g << query (x, y).nod << '\n';
    }
}