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 main() {
  int n, x;
  int a[1001];
  bool hasPred[1001] = {};
  cin >> n >> x;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    if (a[i] != 0) {
      hasPred[a[i]] = true;
    }
  }
  int lengths[1000];
  int size = 0;
  for (int i = 1; i <= n; ++i) {
    if (!hasPred[i] && i != x) {
      lengths[size] = 0;
      bool metX = false;
      for (int j = i; j != 0; j = a[j]) {
        ++lengths[size];
        metX |= j == x;
      }
      if (!metX) {
        ++size;
      }
    }
  }
  int pos = 0;
  for (int i = x; i != 0; i = a[i]) {
    ++pos;
  }
  bool possible[1000] = {};
  possible[0] = true;
  for (int i = 0; i < size; ++i) {
    for (int j = n - 1; j > 0; --j) {
      if (j >= lengths[i]) {
        possible[j] |= possible[j - lengths[i]];
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    if (possible[i]) {
      cout << i + pos << endl;
    }
  }
}
