#include <stdio.h>

int max(int a1, int a2) {
	return a1 > a2 ? a1 : a2;
}

int main() {
	int n = 0;
	int arr[300000];
	while (scanf("%d", &n) > 0) {
		for (int i = 0; i < n; i++) {
			int num = 0;
			scanf("%d", &num);
			arr[i] = num;
		}
		
		int goodPosCount = 0;
		int pairPosCount = 0;
		for (int i = 0; i < n; i++) {
			if (arr[i] == i + 1) goodPosCount++;
			else if (arr[arr[i] - 1] == i + 1) pairPosCount++;
		}
		
		int res = pairPosCount / 2 + max(0, n - goodPosCount - pairPosCount - 1);
		printf("%d\n", res);
	}

	return 0;
}