func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     vector<int> a(n);     for (int i = 0; i < n; ++i) cin >> a[i];     vector<int> ind;     int num = 0, add = 0;     for (int i = 0; i < n; ++i) {       if (a[i] == i)         ++num;       else if (a[a[i]] == i)         add = 2;     }     if (!add) add = 1;     if (num == n) add = 0;     cout << num + add << endl;     return 0;   }   