#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

void solve() {
  int N; cin >> N;
  dsu uf(N);
  for (int i = 0; i < N; i++) {
    int p; cin >> p; p--;
    uf.merge(i, p);
  }
  cout << N - uf.groups().size() << endl;
}

int main() {
  int T; T = 1;
  while (T--) solve();
  return 0;
}