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 pre[1010], Next[1010];
vector<int> length;
int dp[1010];
int main() {
  int i, j, n, x, l;
  while (cin >> n >> x) {
    int pos = -1;
    for (i = 1; i <= n; i++) {
      cin >> pre[i];
      Next[pre[i]] = i;
    }
    for (i = 1; i <= n; i++) {
      if (pre[i] == 0) {
        int cot = 0;
        j = i;
        while (j != 0) {
          cot++;
          if (j == x) {
            pos = cot;
            break;
          }
          j = Next[j];
        }
        if (j == 0) length.push_back(cot);
      }
    }
    l = length.size();
    dp[0] = 1;
    for (i = 0; i < l; i++) {
      for (j = n; j >= 0; j--) {
        if (dp[j - length[i]]) dp[j] = 1;
      }
    }
    for (i = 0; i <= n; i++) {
      if (dp[i]) cout << i + pos << endl;
    }
    memset(dp, 0, sizeof(dp));
    memset(Next, 0, sizeof(Next));
    length.clear();
  }
  return 0;
}
