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;
const int mx = 1e3 + 10;
bool f[2][mx];
int nxt[mx], bef[mx];
int d[mx];
int main() {
  int n, x, u;
  scanf("%d %d", &n, &x);
  memset(bef, -1, sizeof bef);
  memset(nxt, -1, sizeof nxt);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &u);
    if (u != 0) {
      nxt[i] = u;
      bef[u] = i;
    }
  }
  int lx = 0;
  int c = 0;
  for (int i = 1; i <= n; i++) {
    if (bef[i] == -1) {
      u = i;
      int len = 0;
      int lenx = 0;
      while (u != -1) {
        if (u == x || lenx > 0) lenx++;
        len++;
        u = nxt[u];
      }
      if (lenx == 0)
        d[c++] = len;
      else
        lx = lenx;
    }
  }
  int rw = 0;
  f[0][0] = true;
  for (int i = 0; i < c; i++) {
    rw ^= 1;
    for (int s = 0; s < mx; s++) {
      f[rw][s] = f[rw ^ 1][s];
      if (s >= d[i]) f[rw][s] |= f[rw ^ 1][s - d[i]];
    }
  }
  vector<int> ans;
  for (int s = 0; s < n; s++)
    if (f[rw][s]) printf("%d\n", s + lx);
  return 0;
}
