#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i, n) cin >> a[i];
  int ans = 0;
  rep(i, n) {
    if (a[i] == i + 1) continue;
    for (int j = i + 1; j < n; j++) {
      if (a[j] == i + 1) {
        swap(a[i], a[j]);
        ans++;
        break;
      }
    }
  }
  cout << ans << endl;
  return 0;
}