#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	vector<int> arr(n+1);
	
	for(int i = 1; i <= n; i++)
	cin >> arr[i];
	
	unordered_map<int,int> hash;
	int cnt = 0;
	for(int i = 1; i <= n; i++){
		if(arr[i] > n)
		continue;
		
		int req = arr[arr[arr[i]]];
		if(hash.find(req) != hash.end())
		cnt += hash[req];
		
		hash[arr[arr[arr[i]]]]++;
	}
	cout << cnt;
	return 0;
}