#include <bits/stdc++.h>
using namespace std;
ifstream fin ("lca.in");
ofstream fout ("lca.out");
const int Nmax = 400005;
const int Vmax = 20;
int n , Q , L2[Nmax] , rmq[Vmax][1 << Vmax] , niv[Nmax] , euler[Nmax] , poz[Nmax] , dim;
vector < int > L[Nmax / 4];
void DFS(int varf  , int N)
{
    ++dim;
    euler[dim] = varf;
    niv[dim] = N;
    poz[varf] = dim;
    for(auto i : L[varf])
    {
        DFS(i , N + 1);
        ++dim;
        euler[dim] = varf;
        niv[dim] = N;
    }
}
int main()
{
    int x , y , k , p;
    fin >> n >> Q;
    for(int i = 2 ; i <= n ; i++)
    {
        fin >> x;
        L[x] . push_back(i);
    }
    DFS(1 , 0);
    L2[1] = 0;
    rmq[0][1] = 1;
    for(int i = 2 ; i <= dim ; i++)
    {
        L2[i] = L2[i / 2] + 1;
        rmq[0][i] = i;
    }
    for(int i = 1 ; (1 << i) <= dim ; i++)
        for(int j = (1 << i) ; j <= dim ; j++)
    {
        x = niv[rmq[i - 1][j]];
        y = niv[rmq[i - 1][j - (1 << (i - 1))]];
        if(x < y)
            rmq[i][j] = rmq[i - 1][j];
        else rmq[i][j] = rmq[i - 1][j - (1 << (i - 1))];
    }
    while(Q -- )
    {
        fin >> x >> y;
        if(poz[y] < poz[x])
            swap(poz[y] , poz[x]);
        k = L2[poz[y] - poz[x] + 1];
        p = rmq[k][poz[y]];
        if(niv[p] > niv[rmq[k][poz[x] + (1 << k) - 1]])
            p = rmq[k][poz[x] + (1 << k) - 1];
        fout << euler[p] << "\n";
    }
    fin.close();
    fout.close();
    return 0;
}