#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;

int main() {
    int n;
    cin >> n;
    
    int ans = 0;
    dsu uf(n);
    rep(i, n) {
        int p;
        cin >> p;
        --p;
        if (!uf.same(i, p)) ans++;
        uf.merge(i, p);
    }
    
    cout << ans << '\n';
    
    return 0;
}