#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
const int mod = 1000000007;
const double pi = acos(-1.0);
inline void gn(long long& x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int& x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long& x) {
  long long t;
  gn(t);
  x = t;
}
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long x, long long mod) {
  long long t = 1ll;
  while (x) {
    if (x & 1) t = t * a % mod;
    a = a * a % mod;
    x >>= 1;
  }
  return t;
}
const int maxn = 1e4 + 5;
int p[maxn];
int findf(int x) { return x == p[x] ? x : p[x] = findf(p[x]); }
void merge(int x, int y) {
  x = findf(x);
  y = findf(y);
  if (x != y) p[x] = y;
}
int main() {
  int n;
  cin >> n;
  for (int i = (1); i <= (n); i++) p[i] = i;
  for (int i = (1); i <= (n); i++) {
    int x;
    cin >> x;
    merge(i, x);
  }
  int ans = 0;
  for (int i = (1); i <= (n); i++)
    if (i == p[i]) ans++;
  cout << ans << endl;
  return 0;
}
