#include <vector>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cstdlib>
#include <string>
using namespace std;

#define INFILE "lca.in" 
#define OUTFILE "lca.out"
#define NMAX 100010
#define LOGMAX 20

ifstream fin(INFILE);
ofstream fout(OUTFILE);

int n, m, t[NMAX], rmq[NMAX*LOGMAX][LOGMAX], cnt, f[NMAX];
vector<vector<int> > e;

void DFS(int nod) {
   rmq[cnt][0] = nod;
   f[nod] = cnt++;
   for(int i=0; i<e[nod].size(); i++) {
      DFS(e[nod][i]);
      rmq[cnt++][0] = nod;
   }
}

int main() {
   fin >> n >> m;
   e.resize(n+1);
   for(int i=2; i<=n; i++) {
      fin >> t[i];
      e[t[i]].push_back(i);
   }
   cnt = 0;
   DFS(1);

   for(int j=1; (1<<j)<=cnt; j++)
   for(int i=0; i+(1<<j)<=cnt; i++)
      rmq[i][j] = min(rmq[i][j-1], rmq[i+(1<<(j-1))][j-1]);

   for(int i=0; i<m; i++)
   {
      int x, y;
      fin >> x >> y;
      x = f[x];
      y = f[y];
      int l = y-x+1;
      int k = 1;
      while(l>>k) k++;
      k--;
      fout << min(rmq[x][k], rmq[y-(1<<k)+1][k]) << '\n';
   }

   return 0;
}