#define loop(i,from,to) for (int i = from; i < to; ++i)
#include <bits/stdc++.h>

using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;
using std::map;
using std::pair;

const int INF = 1e9+7;
const double eps = 1e-6;


signed main() {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  int n; cin >> n;
  int a, b; cin >> a >> b;
  vector<int> parents(n + 1);
  parents[1] = 1;
  for (int i = 2; i <= n; ++i)
    cin >> parents[i];
  vector<int> PofA;
  int i = a;
  while (i > 1) {
    PofA.emplace_back(i);
    i = parents[i];
  }
  PofA.emplace_back(1);
  i = b;
  int answ;
  bool f = false;
  while (i > 1 && !f) {
    for (int j = 0; j < (int)PofA.size(); ++j)
      if (i == PofA[j]) {
        answ = i;
        f = true;
        break;
      }
    i = parents[i];
  }
  if (!f) answ = 1;
  cout << answ;
  //std::cout << "Hello World!\n";
  return 0;
}