#include <bits/stdc++.h>
using namespace std;
struct dsu{
    vector<int> par, rank, siz;
    dsu(int n) : par(n, -1), rank(n, 0), siz(n, 1){}
    int root(int a){
        if(par[a] == -1) return a;
        else return par[a] = root(par[a]);
    }
    bool sch(int a, int b){
        return root(a) == root(b);
    }
    bool mg(int a, int b){
        a = root(a), b = root(b);
        if(a == b) return false;
        if(rank[a] < rank[b]) swap(a, b);
        par[b] = a;
        if(rank[a] == rank[b]) rank[a]++;
        siz[a] += siz[b];
        return true;
    }
    int sz(int a){
        return siz[root(a)];
    }
};

int main() {
    int n, c = 0; cin >> n;
    dsu uf(n);
    for(int i = 0; i < n; i++){
        int p; cin >> p; p--;
        if(!uf.sch(i, p)) {
            uf.mg(i, p);
            c++;
        }
    }
    cout << c << '\n';
    return 0;
}