20 20
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 10 4
0 1 4 2 7 0 10 0 5 8
 10 7
10 8 6 5 0 0 0 4 3 9
 10 1
8 7 0 2 0 10 0 0 3 5
 10 7
7 9 2 10 0 0 0 3 5 1
 10 2
10 0 9 0 0 4 2 6 8 0
 10 2
0 7 0 10 8 0 4 2 3 0

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 3
4
8
9
 1
5
6
10
 2
4
5
7
8
10
 1
2
6
7
 1
2
3
4
6
7
8
9
 4
5
6
7
8

#include <bits/stdc++.h>
using namespace std;
int E[1010];
int RE[1010];
int main() {
  int N, x;
  cin >> N >> x;
  x--;
  memset(RE, -1, sizeof(RE));
  for (int i = 0; i < N; i++) {
    cin >> E[i];
    if (--E[i] != -1) {
      RE[E[i]] = i;
    }
  }
  int ln = 1;
  for (; E[x] != -1; x = E[x]) {
    ln++;
  }
  vector<int> DP(N + 1, false);
  DP[ln] = 1;
  for (int i = 0; i < N; i++) {
    if (RE[i] != -1) continue;
    int y = i;
    int ln = 1;
    for (; E[y] != -1; y = E[y]) {
      ln++;
    }
    if (x == y) continue;
    for (int i = N; i >= ln; i--) {
      DP[i] |= DP[i - ln];
    }
  }
  for (int i = 1; i <= N; i++) {
    if (DP[i]) {
      cout << i << endl;
    }
  }
  return 0;
}
