#include <iostream>
#include <vector>
#include <queue>
#include <cmath>
#include <climits>


using namespace std;
int A[100010];
int E[100000000];
int H[100000000];
vector<int> Ch[100010];
int pos[100010];

int n, m;
int pos_euler;


int B[100005];
int N;

 int lung_bloc, nr_bloc;



void parcurgere_euleriana(int nod, int h){
    queue<int> Q;
    Q.push(nod);

    E[pos_euler] = nod;
    H[pos_euler] = h;

    pos[nod] = pos_euler;
    pos_euler++;

    while(!Q.empty()){
        int nod = Q.front();


        for(vector<int>::iterator  it = Ch[nod].begin(); it!=Ch[nod].end(); it++){
           parcurgere_euleriana(*it, h+1);
            E[pos_euler] = nod;

             H[pos_euler] = h;
            pos_euler++;

        }


        Q.pop();

    }
}

void afisEuler(){
    for(int i=0; i<pos_euler; i++)
        cout << E[i] << " ";
    cout << endl;

    cout << "H:" << endl;
    for(int i=0; i<pos_euler; i++)
        cout << H[i] << " ";
    cout << endl;


}

int query_secv(int a, int b){
    int minim = H[a];
    int minim_pos = a;
    for(int i=a; i<=b;i++){
        if(H[i] < minim){
            minim = H[i];
            minim_pos = i;
        }
    }
    return minim_pos;
}

int minimEuler(int a, int b){
    int pos_a = pos[a];
    int pos_b = pos[b];

    if(pos_a > pos_b)
        swap(pos_a, pos_b);

    int minim_pos = query_secv(pos_a, pos_b);

    return minim_pos;

}

int main()
{
    freopen("lca.in", "r", stdin);
    freopen("lca.out", "w", stdout);

    scanf("%d %d", &n, &m);

    for(int i=1; i<n; i++)
    {
        cin >> A[i];
        Ch[A[i]].push_back(i+1);
    }



    parcurgere_euleriana(1, 0);
   // afisEuler();

    N = pos_euler;

    lung_bloc = sqrt(N);
    nr_bloc = N/lung_bloc;


//    calcMin();

    int a, b;
    for(int i=0; i<m; i++){
        scanf("%d %d", &a, &b);
        printf("%d\n", E[minimEuler(a, b)] );
    }

    return 0;
}