#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

int n,qs;
vector<int> L[100005];
int EULER[2*100005], NIV[2*100005],FOCC[100005],es;
int RMQ[20][2*100005];
int LOG2[2*100005];

void read(){
    int x;
    in>>n>>qs;
    for(int i=1;i<n;i++){
        in>>x;
        L[x].push_back(i+1);
        L[i+1].push_back(x);
    }
}
void dfs(int st, int par, int niv){
    es++;
    EULER[es]=st;
    NIV[es]=niv;
    if(FOCC[st]==0) // first occurrence
        FOCC[st]=es;
    for(auto x : L[st]){
        if(x!=par){ // no going back ;)
            dfs(x,st,niv+1);
            es++;
            EULER[es]=st;
            NIV[es]=niv;
        }
    }
}
void prep(){
    for(int i=1;i<=es;i++){
        RMQ[0][i]=i;
    }
    for(int i=1;(1<<i)<=es;i++){
        for(int j=1;j<=es;j++){
            if(NIV[RMQ[i-1][j]]<NIV[RMQ[i-1][j+(1<<(i-1))]]){
                RMQ[i][j]=RMQ[i-1][j];
            }
            else{
                RMQ[i][j]=RMQ[i-1][j+(1<<(i-1))];
            }
        }
    }
}
void logs(){
    for(int i=2;i<=es;i++){
        LOG2[i]=LOG2[i/2]+1;
    }
}
int query(int x, int y){
    int lo,hi,log,nelem;
    lo=min(x,y);
    hi=max(x,y);
    nelem=hi-lo+1;
    log=LOG2[nelem];
    if(NIV[RMQ[log][lo]]<NIV[RMQ[log][lo+nelem-(1<<log)]]){
        return RMQ[log][lo];
    }
    else{
        return RMQ[log][lo+nelem-(1<<log)];
    }
}
void solve(){
    int x,y;
    dfs(1,-1,0);
    prep();
    logs();
    for(int i=1;i<=qs;i++){
        in>>x>>y;
        out<<EULER[query(FOCC[x],FOCC[y])]<<"\n";
    }
}
int main(){
    read();
    solve();
    return 0;
}