#include <bits/stdc++.h>

using namespace std;

const int inf = (int)1e9 + 7;

vector<vector<int>> g;

vector<bool> visited;

vector<int> order, pos, lvl, level;

void dfs(int u) {
  visited[u] = true;
  order.push_back(u);
  pos[u] = min(pos[u], (int)order.size() - 1);
  lvl.push_back(level[u]);
  for (int v : g[u]) {
    if (!visited[v]) {
      dfs(v);
      order.push_back(u);
      lvl.push_back(level[u]);
    }
  }
}

void compute_levels(int u) {
  for (int v : g[u]) {
    if (level[v] == inf) {
      level[v] = 1 + level[u];
      compute_levels(v);
    }
  }
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL); cout.tie(NULL);
  ifstream in("lca.in"); ofstream out("lca.out");
  int n, m; in >> n >> m;
  g.resize(n);
  visited.resize(n);
  pos.resize(n, inf);
  vector<int> dad(n - 1);
  level.resize(n, inf);
  for (int i = 0; i < n - 1; ++i) {
    in >> dad[i];
    dad[i] -= 1;
    int u = i + 1, v = dad[i];
    g[u].push_back(v);
    g[v].push_back(u);
  }
  level[0] = 0;
  compute_levels(0);
  dfs(0);
  int euler_size = (int)order.size();
  vector<vector<int>> rmq((int)log2(euler_size) + 2, vector<int>(euler_size, inf));
  for (int i = 0; i < euler_size; ++i) {
    rmq[0][i] = i;
  }
  for (int step = 1; (1 << step) <= euler_size; ++step) {
    for (int i = 0; i - 1 < euler_size - (1 << step); ++i) {
      int last = (1 << (step - 1));
      if (lvl[rmq[step - 1][i]] < lvl[rmq[step - 1][i + last]]) {
        rmq[step][i] = rmq[step - 1][i];
      } else {
        rmq[step][i] = rmq[step - 1][i + last];
      }
    }
  }
  vector<int> lg(2 * n + 1, 0);
  for (int i = 2; i < (int)lg.size(); ++i) {
    lg[i] = 1 + lg[i / 2];
  }
  while (m --) {
    int u, v; in >> u >> v;
    u -= 1;
    v -= 1;
    u = pos[u];
    v = pos[v];
    if (u > v) {
      swap(u, v);
    }
    int len = v - u + 1;
    int step = lg[len];
    if (lvl[rmq[step][u]] < lvl[rmq[step][1 + v - (1 << step)]]) {
      out << 1 + order[rmq[step][u]] << "\n";
    } else {
      out << 1 + order[rmq[step][1 + v - (1 << step)]] << "\n";
    }
  }
  return 0;
}