#include <cstdio>
#define N int(1e5)

int from[N], color[N];
int res, co;

void dfs (int i)
{
  if (color[i] == 0)
    color[i] = co;
  else
  {
    if (color[i] == co)
      res++;
    return;
  }
  dfs(from[i]);
  return;
}
int main()
{
  int n, i, j;
  freopen("pigs.in", "r", stdin);
  freopen("pigs.out", "w", stdout);
  scanf("%d", &n);
  for (i = 0; i < n; i++)
  {
    scanf("%d", &j);
    from[i] = j - 1;
  }
  for (i = 0; i < n; i++)
  {
    if (color[i] == 0)
    {
      co++;
      dfs(i);
    }
  }
  printf("%d\n", res);
}