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

using namespace std;

const int Nmax = 100005;

int n, m, top, log2[Nmax], first[Nmax];

bool viz[Nmax];
vector<int> L[Nmax];
vector<pair<int, int>> E;
pair<int, int> dp[Nmax][22];
//dp[i][j] = idx nodului cu depth min in E[] inc de la i cu lung 2^j
//first = niv, second = nodul

int lenE;

void preCalc(){
    log2[1] = 0;
    for(int i = 2; i <= Nmax; i++){
        log2[i] = log2[i/2] + 1;
    }
}

void dfs(int nod, int niv){
    E.push_back({nod, niv});
    if(!viz[nod]){
        first[nod] = E.size() - 1;
        viz[nod] = true;
    }
    for(auto vec : L[nod]){
        dfs(vec, niv+1);
        E.push_back({nod, niv});
    }
}

void RMQ(){
    for(int i = 0; i < lenE; i++){
        dp[i][0] = {E[i].second , E[i].first};
    }

    for(int p = 1; (1 << p) <= lenE; p++){
        for(int i = 1; i + (1 << (p-1)) <= lenE; i++){
            dp[i][p] = min(dp[i][p-1], dp[i + (1 << (p-1))][p-1]);
        }
    }
}

int query(int st, int dr){
    int l = dr - st + 1;
    int p = log2[l];
    int jum = (1 << p);

    return min(dp[st][p], dp[dr - jum + 1][p]).second;
}

int main()
{
    ifstream fin("lca.in");
    ofstream fout("lca.out");
    fin >> n >> m;
    first[1] = -1;
    for(int i = 2; i <= n; i++){
        int aux;
        fin >> aux;
        L[aux].push_back(i);
        first[i] = -1;
    }
    preCalc();
    dfs(1, 0);
    lenE = E.size();
    RMQ();

    while(m--){
        int u, v;
        fin >> u >> v;
        u = first[u];
        v = first[v];
        if(u > v){
            swap(u, v);
        }
        fout << query(u, v) << "\n";
    }

    return 0;
}