// #include <bits/stdc++.h>
#include <string.h>

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <ciso646>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define rep(i, l, r) for (int i = int(l), rr = int(r); i < rr; ++i)
#define repin(i, l, r) for (int i = int(l), rr = int(r); i <= rr; ++i)
#define rep0(i, n) rep(i, 0, n)
#define rrep(i, l, r) for (int i = int(r) - 1, ll = int(l); i >= ll; --i)
#define rrepin(i, l, r) for (int i = int(r), ll = int(l); i >= ll; --i)
#define rrep0(i, n) rrep(i, 0, n)

#define fi first
#define se second

#include <atcoder/dsu>

#include <algorithm>
#include <cassert>
#include <vector>

namespace rklib {

template <class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
bool chmin_non_negative(T &a, const T &b) {
    if (a < 0 || a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
T div_floor(T a, T b) {
    if (b < 0) a *= -1, b *= -1;
    return a >= 0 ? a / b : (a + 1) / b - 1;
}

template <class T>
T div_ceil(T a, T b) {
    if (b < 0) a *= -1, b *= -1;
    return a > 0 ? (a - 1) / b + 1 : a / b;
}

}  // namespace rklib


using namespace std;
using namespace rklib;

using lint = long long;
using pii = pair<int, int>;
using pll = pair<lint, lint>;

int main() {
    int n;
    scanf("%d", &n);
    atcoder::dsu uf(n);
    rep0(i, n) {
        int p;
        scanf("%d", &p);
        --p;
        uf.merge(i, p);
    }
    int ans = 0;
    rep0(i, n) if (uf.leader(i) == i) ans += uf.size(i) - 1;
    printf("%d\n", ans);
}