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 xpos;
int n, x;
vector<int> lens;
int head[1050], back[1050], dp[1050];
int main() {
  cin >> n >> x;
  for (int i = 1; i <= n; i++) {
    cin >> head[i];
    back[head[i]] = i;
  }
  for (int i = 1; i <= n; i++) {
    if (head[i]) continue;
    int len = 1;
    int j = i;
    if (j == x) {
      xpos = len;
      len = 0;
    }
    while (back[j] && len) {
      if (j == x) {
        xpos = len;
        len = 0;
        break;
      }
      len++;
      j = back[j];
    }
    if (len) lens.push_back(len);
  }
  dp[0] = 1;
  for (int i = 0; i < lens.size(); i++) {
    for (int j = n + 1; j - lens[i] >= 0; j--) {
      dp[j] |= dp[j - lens[i]];
    }
  }
  for (int i = 0; i <= n + 1; i++) {
    if (dp[i] && i + xpos) cout << i + xpos << endl;
  }
  return 0;
}
