#include <stdio.h>
#include <math.h>

int arr[200001];
int main() {
	int N;
	while (scanf("%d\n", &N) == 1) {
		int i;
		for (i=1; i<=N; i++) {
			scanf("%d ", arr+i);
		}
		int cnt=0;
		i=1;
		while (i<=N) {
			if (i != arr[i]) {
				int a=arr[i];
				arr[i] = arr[a];
				arr[a] = a;
				cnt++;
			} else {
				i++;
			}
		}
		printf("%d\n", cnt);
	}

	return 0;
}