#include <inttypes.h>
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdalign>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>

// #include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i, n) for(int i=0;i<(int)(n);i++)
#define pb push_back
#define pob pop_back
#define eb emplace_back
#define nall(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define yesno(a) cout<<(a?"YES\n":"NO\n")
#define accu accumulate
#define bs binary_search
#define lb lower_bound
#define ub upper_bound
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
using namespace std;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template<class T> using pq = priority_queue<T>;
template<class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
template<class T> using vec = vector<T>;
template<class T> using vv = vector<vector<T>>;
template<class T> using vvv = vector<vv<T>>;
const ll MOD = 998244353ll;
// const ll MOD = 1000000007ll;

struct dsu{
    vector<int> par;
    vector<int> sz;

    dsu(int n){
        par.resize(n);
        sz.assign(n, 1);
        for (int i = 0; i < n; i++) par[i] = i;
    }

    int root(int x){
        if (par[x] == x) return x;
        return par[x] = root(par[x]);
    }

    void merge(int x, int y){
        x = root(x);
        y = root(y);
        if (x == y) return;
        if (sz[x] < sz[y]) swap(x, y);
        par[y] = x;
        sz[x] += sz[y];
        return;
    }

    bool same(int x, int y){
        return root(x) == root(y);
    }

    int size(int x){
        return sz[root(x)];
    }
};

void solve();
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(20);
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}

void solve(){
    int N;
    cin >> N;
    vec<int> A(N);

    dsu uf(N);
    rep(i, N){
        int x;
        cin >> x, x--;
        uf.merge(i, x);
    }

    map<int, int> R;
    rep(i, N) R[uf.root(i)]++;

    int ans = 0;
    for (auto [k, v] : R) ans += v-1;
    cout << ans << endl;
}