#include <bits/stdc++.h>

using namespace std;
ifstream fin("lca.in");
ofstream fout("lca.out");

int n, m, u, w, viz[100001], p[100001], dp[20][100001], p1, p2;
vector<int>g[100001];
vector<int>e[2];
void dfs(int k, int lvl)
{
    viz[k]=1;
    e[0].push_back(k);
    p[k] = e[0].size() - 1;
    e[1].push_back(lvl);
    for(int i=0; i<g[k].size(); i++)
    {
        if(viz[g[k][i]]==0)
        {
            dfs(g[k][i], lvl+1);
            e[0].push_back(k);
            e[1].push_back(lvl);
        }

    }
}
void rmq()
{
    for(int i=0; i< e[0].size(); i++)
        dp[0][i] = i;

    for(int i=1; (1 << i) < e[0].size(); i++)
    {
        for(int j=0; j <= e[0].size() - (1 << i); j++)
        {
            if( e[1][dp[i-1][j]] < e[1][dp[i-1][j+ (1 << (i-1) )]] )
                dp[i][j] = dp[i-1][j];
            else
                dp[i][j] = dp[i-1][j+ (1 << (i-1) )];
        }
    }
}
int main()
{
    fin >> n >> m;
    for(int i=1; i<n; i++)
    {
        fin >> u ;
        g[i+1].push_back(u);
        g[u].push_back(i+1);
    }
    dfs(1, 0);
    rmq();
    for(w=1; w<=m; w++)
    {
        fin >> p1 >> p2;
        p1=p[p1];
        p2=p[p2];

        if(p1 > p2)
            swap(p1, p2);

        int L=log2(p2-p1+1);

        if(e[1][dp[L][p1]] < e[1][dp[L][p2-(1 << L) + 1]])
            fout << e[0][dp[L][p1]] << endl;

        else
            fout << e[0][dp[L][p2-(1 << L) + 1]] << endl;

    }

    return 0;
}