Submission #890744

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Source Code Expand

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


typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<vvd> vvvd;
typedef pair<int, int> pii;
typedef vector<pii> vpii;

#define pb push_back
#define mp make_pair
#define snd second
#define fst first
#define debug printf("--%d--\n",__LINE__)
#define ll long long int

int main(void){
	int n;
	cin >> n;
	int a[n];
	for(int i=0;i<n;i++) cin >> a[i];
	int ret = 0;
	for(int i=0;i<n;i++){
		if (i < a[i] && a[a[i]]==i) ret++;
	}
	cout << ret << endl;
	
	
	
	return 0;
}

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