#include <bits/stdc++.h>
#define pb push_back

using namespace std;

const int nax = 1e5 + 5;

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

vector<int> graf[nax];
int euler[nax >> 1], nivel[nax >> 1], prima[nax];
int arb[nax << 1][20];
int lg[nax];
int n, m, dim;

// formez lista muchiilor de adiacenta
void Read()
{
    int i, x;
    f >> n >> m;
    for(i = 2; i <= n; ++i)
    {
        f >> x;
        graf[x].pb(i);
    }
}

// formez reprezentarea euler, nivelul fiecarui nod din reprezentarea euler
// cat si prima aparitie a fiecarui element in reprezentarea euler
void Euler(int nod, int lvl)
{
    euler[dim] = nod;
    nivel[dim] = lvl;
    prima[nod] = dim++;
    for(int& it : graf[nod])
    {
        Euler(it, lvl + 1);
        euler[dim] = nod;
        nivel[dim++] = lvl;
    }
}

// formez vectorul de logaritmi
// formez matricea arb din rmq
void PreProcessing()
{
    int i, j;
    lg[1] = 0;
    for(i = 2; i <= dim; ++i)
        lg[i] = lg[i >> 1] + 1;

    for(i = 0; i < dim; ++i)
        arb[i][0] = euler[i];

    for(j = 1; (1 << j) < dim; ++j)
        for(i = 0; i + (1 << j) < dim; ++i)
            arb[i][j] = min( arb[i][j-1], arb[i + (1 << (j-1))][j-1] );
}

int Rmq(int& st, int& dr)
{
    if(st > dr)
    {
        st ^= dr;
        dr ^= st;
        st ^= dr;
    }

    int range = dr - st + 1;
    int power = lg[range];
    return min(arb[st][power], arb[dr - (1 << power) + 1][power]);
}

int main()
{
    Read();
    Euler(1, 0);

    PreProcessing();

    int x, y;
    while(m--)
    {
        f >> x >> y;
        --x; --y;
        g << Rmq(prima[x], prima[y]) << "\n";
    }

//    for(int i = 0; i < dim; ++i)
//    {
//        for(int j = 0; j < lg[dim-i]; ++j)
//            g << arb[i][j] << " ";
//        g << "\n";
//    }

    return 0;
}