#include <iostream>
#include <map>
#include <set>
#include <vector>
#include <queue>

#define DEBUG

#ifdef DEBUG
	#define DBG if (1)
#else
	#define DBG if (0)
#endif

#define PA(arr, n) DBG for (int i = 0; i < n; i++) printf("%d%c", arr[i], "\n "[i < n - 1])
#define PD(n) DBG printf("DEBUG %d\n", n); 
#define PDBL(n) DBG printf("DEBUG %lf\n", n);

using namespace std;

int main () {

	int n, k;
	while(scanf("%d", &n) == 1){
		vector<int> arr(n+1);
		for(int i = 1; i <= n; i++)
			scanf("%d", &arr[i]);		
		int i = 1, output = 0;
		while(i <= n){
			if(arr[i] == i){
				i++;
				continue;			
			}
			swap(arr[i], arr[arr[i]]);
			output++;
		}
		printf("%d\n", output);
	
	}

	return 0;

}