#include <iostream>
using namespace std;

int v[300010];
int ind[300010];
int main(){
	int n, tmp, count, poz;
	while(cin >> n){
		count =0; 
		for(int i=1; i < 300010; i++) v[i] = 0;
		for(int i=1; i <= n; i++){
			cin >> v[i];
			ind[v[i]] = i;
		}

		for(int i=1; i <= n; i++){
			if(v[i] != i){
				poz = ind[i];
				v[poz] = v[i];
				ind[v[i]] = poz;
				++count;
/*
				tmp = v[v[i]];
				cout << tmp << " za " << v[i] << "\n";
				v[v[i]] = v[i];
				v[i] = tmp;
				count++;
				*/
			}
		}
		cout << count << "\n";
	}

	return 0;
}