#include <fstream>
#include <vector>
#define DIM 200010
using namespace std;

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

int n, m, k, a, b, C, Pow[DIM], E[DIM], N[DIM], F[DIM], D[20][DIM];
vector <int> L[DIM];

void euler(int nod, int niv){

    E[++k] = nod;
    N[k] = niv;
    F[nod] = k;

    for(int i = 0; i < L[nod].size(); i ++)
    {
            euler(L[nod][i], niv + 1);
            E[++k] = nod;
            N[k] = niv;
    }
}

void citire(){

    fin >> n >> m;

    int x;

    for(int i = 2; i <= n; i ++)
    {
        fin >> x;
        L[x].push_back(i);
    }

}

void solve(){

    euler(1,1);

    Pow[1] = 0;

    for(int i = 2; i <= n; i ++)
    {
        Pow[i] = Pow[i / 2] + 1;
    }

    for(int i = 1; i <= k; i ++)
    {
        D[0][i] = i;
    }
    // RMQ preprocesare : start;
    for(int i = 1; (1 << i) <= k; i ++)
    {
        for(int j = 1; j<= k; j ++)
        {
            D[i][j] = D[i - 1][j];

            if( (j + (1 << i - 1) <= k) && (N[ D[i][j] ] > N[ D[i - 1][ j + (1 << (i - 1)) ] ]) )
            {
                D[i][j] = D[i - 1][j + (1 << (i - 1))];
            }
        }
    }
    // RMQ preprocesare : end;
    // RMQ query : start;
    for(int i = 1; i <= m; i ++)
    {
        fin >> a >> b;

        a = F[a];
        b = F[b];

        if(a > b)
        {
            switch(a, b);
        }

        C = Pow[b - a + 1];

        fout << min(N[ D[C][a] ], N[ D[C][b - ( 1 << C ) + 1] ] ) << '\n';
    }
    // RMQ query : end;
}

int main()
{
    citire();
    solve();

    return 0;
}