/**
 *    author:  zjs
 *    created: 01.09.2026 19:51:18
**/
#include <bits/stdc++.h>
#include <cassert> // <bits/stdc++.h> does not include cassert since GCC 16.
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin >> n;
    vector<int> a(n + 1);
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    
    int ans = 0;
    vector<int> vis(n + 1);
    int t = 0;
    for (int i = 1; i <= n; i++) {
        if (!vis[i]) {
            ++t;
            int j = i;
            while (!vis[j]) {
                vis[j] = t;
                j = a[j];
            }
            if (vis[j] == t)
                ans++;
        }
    }
    cout << ans << '\n';
}