#include <stdio.h>
 
int main(void) {
	//scan data
	int n;
	scanf("%d",&n);
	int Friend[50000];
	int  i;
	for(i=0;i<n;i++)
		scanf("%d",&Friend[i]);
 
	//process data
	int visited[50000]={0};
	//int group[50000]={0};
	int m=0;
	int *iptr=Friend;
	for(i=0;i<n;i++){
		if(visited[i]==0){
			iptr=&Friend[i];
			visited[i]=1;
			m++;
			//group[i]=m;
			while(*iptr!=i){
				visited[*iptr]=1;
				//group[*iptr]=m;
				iptr=&Friend[*iptr];
			}
		}
	}
 
	//print data
	printf("%d",m);
	return 0;
}
 

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