/* -*- coding: utf-8 -*-
 *
 * 3650.cc:  No.3650 Teleportation Cycles - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

/* global variables */

int as[MAX_N], gs[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", as + i), as[i]--;

  fill(gs, gs + n, -1);
  int gn = 0, lp = 0;

  for (int st = 0; st < n; st++)
    if (gs[st] < 0) {
      int id = gn++, u = st;
      while (gs[u] < 0) gs[u] = id, u = as[u];
      if (gs[u] == id) lp++;
    }

  printf("%d\n", lp);
  
  return 0;
}