#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 1;


struct union_find{
    vector<int> par;
    vector<int> siz;
    
    union_find(int n) : par(n), siz(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 unite(int x, int y){
        int rx = root(x);
        int ry = root(y);
        if (rx == ry) return;
        if (siz[rx] < siz[ry]) swap(rx, ry);
        siz[rx] += siz[ry];
        par[ry] = rx;
    }
 
    bool same(int x, int y){
        int rx = root(x);
        int ry = root(y);
        return rx == ry;
    }
 
    int size(int x){
        return siz[root(x)];
    }
};

void solve(){
    ll n; cin >> n;
    union_find uf(n);
    rep(i, n){
        ll p; cin >> p;
        uf.unite(i, p-1);
    }

    ll ans = 0;
    rep(i, n) if(uf.root(i)==i) ans += uf.size(i)-1;

    cout << ans << endl;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int T=1;
    //cin >> T;
    while(T--) solve();
}