#include <bits/stdc++.h>

using namespace std;

vector <int> lAd[100001];
int N , Q , euler[200005] , K , niv[100001] , poz[200005];
int dp[18][200005] , E[200005];

void DFS (int V , int P)
{
    euler[++K] = V;
    niv[V] = 1 + niv[P];
    poz[V] = K;
    for (int U : lAd[V])
    {
        if(P != U)
        {
            DFS(U , V);
            euler[++K] = V;
        }
    }
}

void Precalc ()
{
    for (int i = 1; i <= K; ++i)
        dp[0][i] = euler[i];
    for (int i = 1; (1 << i) <= K; ++i)
        for (int j = 1; j <= K; ++j)
        {
            dp[i][j] = dp[i - 1][j];
            if(j + (1 << (i - 1)) <= K && niv[dp[i - 1][j]] > niv[dp[i - 1][j + (1 << (i - 1))]])
                dp[i][j] = dp[i - 1][j + (1 << (i - 1))];
        }
    E[1] = 0;
    for (int i = 2; i <= K; ++i)
        E[i] = 1 + E[i / 2];
}

int Query (int l , int r)
{
    l = poz[l] , r = poz[r];
    int lg = r - l + 1 , p = E[lg] , x = (1 << p);
    int a = dp[p][l];
    int b = dp[p][r - x + 1];
    if(niv[a] < niv[b])
        return a;
    return b;
}

int main()
{
    ifstream fin ("lca.in");
    ofstream fout ("lca.out");
//    ios_base :: sync_with_stdio(false);
//    cin.tie(nullptr);
    fin >> N >> Q;
    for (int i = 2; i <= N; ++i)
    {
        int X;
        fin >> X;
        lAd[X].push_back(i);
        lAd[i].push_back(X);
    }
    DFS(1 , 0);
    Precalc();
    while (Q --)
    {
        int X , Y;
        fin >> X >> Y;
        fout << Query(X , Y) << "\n";
    }
}