#include <bits/stdc++.h>
#include <cstdlib>

using namespace std;

int main(int argc, char** argv) {
    ios::sync_with_stdio(false);
   
    int N, x;
    while(cin >> N) {
        vector<int> a(N);
        for(int i = 0; i < N; ++i) {
            cin >> x; a[i] = x-1;
        }
        int n = 0, t = 0;
        for(int i = 0; i < N; ++i) {
//            cout << n << " " << t << '\t' << i << " " << a[i] << endl;
            if (a[i] == i) continue;
            if (i == a[a[i]]) {
                if (i < a[i]) {n += 1;continue;}
                else continue;
            }
            t++;
//            cout << i << " " << a[i] << " " << n << " " << t << endl;
            
            
        }
//        cout << endl << endl;
//        cout << n << " "<< t << endl;
        cout << n + max(0, t-1) << endl;
        
    }
}