#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <stdlib.h>
#include <stdio.h>

int main()
{
	int *pole;
	int n;
	int i;
	int temp,temp2;
	int swaps=0;
	while(scanf("%d",&n)>0)
	{
		pole = (int*)malloc(n*sizeof(int));
		for(i=0;i<n;i++){
			scanf("%d",&pole[i]);
		}	
		for(i=0;i<n;i++){
			if(pole[i]!= i + 1){
				
			temp=pole[i];
			temp2=pole[pole[i]-1];
			pole[i]=temp2;
			pole[temp-1]=temp;
		
			swaps++;
			
			i--;
		
		}
	}
	printf("%d\n",swaps);
	swaps = 0;
	free(pole);
	}
	return 0;
}