#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("sse4")
using namespace std;
using ll = long long;
using db = long double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
template <class T>
using V = vector<T>;
template <class T>
using PR = pair<T, T>;
template <class T, size_t SZ>
using AR = array<T, SZ>;
template <class T>
using pqg = priority_queue<T, vector<T>, greater<T>>;
const int MX = 2e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = 1e18;
const db PI = acos((db)-1);
const int xdir[4] = {1, 0, -1, 0}, ydir[4] = {0, 1, 0, -1};
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int bits(int x) { return x == 0 ? 0 : 31 - __builtin_clz(x); }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
template <class T>
bool ckmin(T& a, const T& b) {
  return b < a ? a = b, 1 : 0;
}
template <class T>
bool ckmax(T& a, const T& b) {
  return a < b ? a = b, 1 : 0;
}
template <class T, class U>
T fstTrue(T lo, T hi, U first) {
  hi++;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo) / 2;
    first(mid) ? hi = mid : lo = mid + 1;
  }
  return lo;
}
template <class T, class U>
T lstTrue(T lo, T hi, U first) {
  lo--;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo + 1) / 2;
    first(mid) ? lo = mid : hi = mid - 1;
  }
  return lo;
}
template <class T>
void remDup(V<T>& v) {
  sort(begin(v), end(v));
  v.erase(unique(begin(v), end(v)), end(v));
}
template <typename T1, typename T2>
str to_string(pair<T1, T2> p);
template <typename T1, typename T2, typename T3>
str to_string(tuple<T1, T2, T3> p);
template <typename T1, typename T2, typename T3, typename T4>
str to_string(tuple<T1, T2, T3, T4> p);
str to_string(const str& S) { return '"' + S + '"'; }
str to_string(const char* S) { return to_string((str)S); }
str to_string(bool b) { return b ? "true" : "false"; }
template <class T>
str to_string(complex<T> c) {
  stringstream ss;
  ss << c;
  return ss.str();
}
template <size_t SZ>
str to_string(bitset<SZ> v) {
  str res = "";
  for (int i = (0); i < (SZ); ++i) res += char(v[i] + '0');
  return res;
}
template <typename T>
str to_string(T v) {
  bool fst = 1;
  str res = "";
  for (const auto& x : v) {
    if (!fst) res += " ";
    fst = 0;
    res += to_string(x);
  }
  return res;
}
template <typename T1, typename T2>
str to_string(pair<T1, T2> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
void DBG() { cerr << endl; }
template <typename Head, typename... Tail>
void DBG(Head H, Tail... T) {
  cerr << " " << to_string(H);
  DBG(T...);
}
void setPrec() { cout << fixed << setprecision(15); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIn(str name) { freopen(name.c_str(), "r", stdin); }
void setOut(str name) { freopen(name.c_str(), "w", stdout); }
void setIO(str name = "") {
  unsyncIO();
  setPrec();
  if ((int)((name).size())) setIn(name + ".in"), setOut(name + ".out");
}
struct DSU {
  vi e;
  void init(int N) { e = vi(N, -1); }
  int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); }
  bool unite(int x, int y) {
    if (((x = get(x)) == (y = get(y)))) return 0;
    if (e[x] > e[y]) swap(x, y);
    e[x] += e[y];
    e[y] = x;
    return 1;
  }
};
int32_t main() {
  setIO();
  int n;
  cin >> n;
  DSU D;
  D.init(n);
  for (int i = (0); i < (n); ++i) {
    int x;
    cin >> x;
    --x;
    D.unite(i, x);
  }
  set<int> res;
  for (int i = (0); i < (n); ++i) res.insert(D.get(i));
  cout << (int)((res).size()) << "\n";
}
