#include <bits/stdc++.h>

using namespace std;

void DFS(int,int);
void rmq();
vector <int> G[100005];
int solve(int,int);
int n,m,t[100005],niv[100005],ans[20][100005],viz[100005],viz1[100005],pe[200005],npe,M[20][100005];
int main(){
    freopen("lca.in","r",stdin);
    freopen("lca.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (int i=2;i<=n;i++){
        scanf("%d",&t[i]);
        G[i].push_back(t[i]);
        G[t[i]].push_back(i);
    }
    DFS(1,0);
    rmq();
    for (int i=1;i<=m;i++){
        int a,b;
        scanf("%d%d",&a,&b);
        printf("%d\n",solve(viz[a],viz[b]));
    }
}

void DFS(int node,int level){
    viz1[node]=1;
    pe[++npe]=node;
    niv[npe]=level;
    if (!viz[node]){
        viz[node]=npe;
    }
    for (int i=0;i<G[node].size();i++){
        int nod=G[node][i];
        if (!viz1[nod]){
            DFS(nod,level+1);
            pe[++npe]=node;
            niv[npe]=level;
        }
    }
}

int solve(int a,int b){
    if (b<a){
        swap(b,a);
    }
    int l=b-a+1;
    if (M[(int)log2(l)][a]<M[(int)log2(l)][b-(1<<(int)log2(l))+1]){
        return ans[(int)log2(l)][a];
    }
    else {
        return ans[(int)log2(l)][b-(1<<(int)log2(l))+1];
    }
}

void rmq(){
    for (int i=1;i<=npe;i++){
        M[0][i]=niv[i];
        ans[0][i]=pe[i];
    }
    for (int j=1;(1<<j)<=npe;j++){
        for (int i=1;i+(1<<(j-1))<=npe;i++){
            M[j][i]=min(M[j-1][i],M[j-1][i+(1<<(j-1))]);
            if (M[j-1][i]>M[j-1][i+(1<<(j-1))]){
                ans[j][i]=ans[j-1][i+(1<<(j-1))];
            }
            else {
                ans[j][i]=ans[j-1][i];
            }
        }
    }
}