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

1
2 2 1  0
6 2 6 2 4 2  1 
1 1 
 2 
2 2 2 2 6 2 6 6 
 5 
2 3 4 5 11 7 8 9 10 11 11 11 14 15 11 17 18 11 
 6 
1 1 1 1 1 1 1 
 1
4 3 3 6 3 5 2  1
7 5 3 1 3 1 5  4 
1 6 4 1 1 1 1 

#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long n;
  cin >> n;
  vector<long long> a(n);
  long long b = -1;
  long long ans = -1;
  for (long long i = (0); i < (n); i++) cin >> a[i], a[i]--;
  for (long long i = (0); i < (n); i++)
    if (i == a[i]) a[i] = b, b = i, ans++;
  for (long long i = (0); i < (n); i++)
    if (a[i] == -1) a[i] = i, b = i;
  vector<long long> use(n, 0);
  for (long long i = (0); i < (n); i++)
    if (!use[i] && i != b) {
      long long fl = 0, c = i;
      while (1) {
        use[c] = i;
        c = a[c];
        if (use[c] != i) break;
        if (use[c] == i) {
          fl = 1;
          break;
        }
      }
      if (fl)
        if (b != -1) a[c] = b, ans++;
      if (fl)
        if (b < 0) b = c, a[c] = c, ans = 1;
    }
  cout << ans << '\n';
  for (long long i = (0); i < (n); i++) cout << (a[i] + 1) << ' ';
  return 0;
}
