#include <iostream>



using namespace std;

int komnata[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) {

		
		bool vsetkoOk = true;
		for (int i = 1; i <= pocetKomnat; i++)
		{
			cin >> komnata[i];
			if (komnata[i] != i) vsetkoOk = false;
		}


		int pocetSwapov = 0;

		if(!vsetkoOk) {
			for (int k = 1; k <= pocetKomnat; k++)
			{
				if (k != komnata[k]) {
					for (int p = k+1; p <= pocetKomnat; p++)
					{
						if (komnata[p] ==k) {
							komnata[p] = komnata[k];
							komnata[k] = k;
							pocetSwapov++;
							//vypis(komnata,pocetKomnat);
							break;
						}
					}
				}
			}
		}
		cout << pocetSwapov << endl;
	}



	return 0;
}