#ifndef ONLINE_JUDGE
#define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll=long long;
using ld=long double;
using st=string;
using P=pair<ll,ll>;
typedef atcoder::modint mint;
ll inf=9e18;
template<class... T>
constexpr auto max(T... a){return max(initializer_list<common_type_t<T...>>{a...});}
template<class... T>
constexpr auto min(T... a){return min(initializer_list<common_type_t<T...>>{a...});}
template<typename T, int s, int i = 0>
auto vec(const ll (&sizes)[s], const T& init = T()){
  if constexpr(i < s) return vector(sizes[i], vec<T, s, i+1>(sizes, init));
  else return init;
}


int main(){
  ll n,ans=0;
  cin>>n;
  auto v=vec<ll>({n},0);
  for(ll i=0;i<n;i++){
    cin>>v[i];
  }
  auto looked=vec<bool>({n},0);
  for(ll i=0;i<n;i++){
    if(looked[i]==0){
      ll x=i;
      while(looked[x]==0){
        looked[x]=1;
        x=v[x]-1;
      }
      ans++;
    }
  }
  cout<<ans<<"\n";

}