#include <bits/stdc++.h>
using namespace std;
#define zero(x) (x & (-x))
ifstream fin("lca.in");
ofstream fout("lca.out");
const int  MAXN = 1e5 + 3;
const int LOGMAX = 25;
const int INF = 1e8;
vector <int> g[MAXN];
int first[MAXN], euler[2 * MAXN], dist[MAXN];
int lg[2 * MAXN], rmq[LOGMAX][2 * MAXN], indice;
bool seen[MAXN];
void buildEUL(int node, int papa){
    if(seen[node]) return;
    seen[node] = true;
    euler[indice] = node;
    first[node] = indice++;
    dist[node] = dist[papa] + 1;
    for(auto x: g[node]){
        buildEUL(x, node);
        euler[indice++] = node;
    }
}
void buildLOG(){
    for(int i = 2; i <= indice; ++i)
        lg[i] = lg[i / 2] + 1;
    for(int i = 0; i < indice; ++i)
        rmq[0][i] = i;
}
void buildRMQ(){
    for(int i = 1; i <= lg[indice - 1]; ++i){
        for(int j = 0; j + (1 << i) < indice; ++j){
            if(dist[euler[rmq[i - 1][j]]] < dist[euler[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))];
        }
    }
}
int buildSOL(int x, int y){
    int dif = y - x + 1;
    int logaritm = lg[dif];
    if(dist[euler[rmq[logaritm][x]]] < dist[euler[rmq[logaritm][y - (1 << logaritm) + 1]]])
        return euler[rmq[logaritm][x]];
    else return euler[rmq[logaritm][y - (1 << logaritm) + 1]];
}
int main(){
    int n, m; fin >> n >> m;
    for(int i = 1; i < n; ++i){
        int x; fin >> x;
        g[x].push_back(i + 1);
    }
    buildEUL(1, 0);
    buildLOG();
    buildRMQ();
    for(int i = 1; i <= m; ++i){
        int x, y; fin >> x >> y;
        if(first[x] > first[y]) swap(x , y);
        fout << buildSOL(first[x], first[y]) << '\n';
    }
    return 0;
}