#include <iostream>



using namespace std;


int prisera[2000001];
int vymena[2000001];

void vypis(int pole[], int max) {
	cout << "==============================" << endl;
	for (int i = 1; i <= max; i++) {
		cout << i << " " << pole[i] << endl;
	}
	cout << "==============================" << endl;
}

int main() {
	

	int pocetKomnat;
	while (cin >> pocetKomnat) {

		int premenna;
		
		for (int k = 1; k <= pocetKomnat; k++)
		{
			cin >> premenna;
			prisera[k] = premenna;
			vymena[premenna] = k;
		}

		int pocetSwapov = 0;
		
			for (int k = 1; k <= pocetKomnat; k++)
			{
				if (k != prisera[k]) {
					int pom = prisera[k];
					prisera[k] = k;
					prisera[vymena[k]] = pom;
					vymena[pom] = vymena[k];
					vymena[k] = 0;
					//vypis(prisera,pocetKomnat);
					pocetSwapov++;
				}
			}
		
		cout << pocetSwapov << endl;
	}

	return 0;
}