#include 
#include 
#include 
#include 
using namespace std;
const int maxn=500000;

int main() {
    int n;
    cin >> n;
    
    int nodes_as_trees = 0;
    set st;
    for(int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        if(x == i) {
            nodes_as_trees++;
        }
        else {
            st.insert(x);
        }
    }
    cout << (int) st.size() / 2 + nodes_as_trees << endl;

    return 0;
}