#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int tab[n];     long long s = 0;     for (int i = 0; i < n; i++) {       cin >> tab[i];       if (i == tab[i]) {         s++;         tab[i] = -1;       }     }     bool bo = false;     for (int i = 0; i < n; i++) {       if (tab[i] != -1) {         if (tab[tab[i]] == i) {           s += 2;           bo = false;           break;         }         bo = true;       }     }     if (bo) s++;     cout << s;   }   