#include <stdio.h>

int nums[200000];

int solve(int N)
{
  int ret = 0;
  for(int i = 0; i < N; i++) {
    while(nums[i] != i+1) {

      int tmp = nums[i];
      nums[i] = nums[tmp-1];
      nums[tmp-1] = tmp;
      ret++;
    }

  }
  return ret;
}



int main()
{
  int N;


  while(scanf("%d", &N) != EOF ) {
    int i = 0;
    while(i < N)
      scanf("%d", &nums[i++]);

    printf("%d\n", solve(N));
  }
}