#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template <class T>
using MaxHeap = std::priority_queue<T>;
template <class T>
using MinHeap = std::priority_queue<T, vector<T>, greater<T>>;
#define rep2(i, n) for (ll i = 0; i < (n); i++)
#define rep3(i, l, r) for (ll i = (l); i < (r); i++)
#define rrep2(i, n) for (ll i = n; i-- > 0;)
#define rrep3(i, r, l) for (ll i = (r); i-- > (l);)
#define overload(a, b, c, d, ...) d
#define rep(...) overload(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define rrep(...) overload(__VA_ARGS__, rrep3, rrep2)(__VA_ARGS__)
#define all(x) begin(x), end(x)
bool chmin(auto& lhs, auto rhs) {
    return lhs > rhs ? lhs = rhs, 1 : 0;
}
bool chmax(auto& lhs, auto rhs) {
    return lhs < rhs ? lhs = rhs, 1 : 0;
}
struct IOIO {
    IOIO() {
        std::cin.tie(0)->sync_with_stdio(0);
    }
} ioio;

void solve() {
    int n;
    cin >> n;
    vector<int> P(n);
    rep(i, n) cin >> P[i], P[i]--;
    vector graph(n, vector<int>());
    rep(i, n) if (P[i] != -1) graph[P[i]].push_back(i);

    vector<int> contains(n);
    rep(i, n) if (P[i] != -1) contains[P[i]] = true;
    vector<int> ans(n);
    rep(p, n) {
        int i = P[p];
        if (i == -1) continue;
        bool ok = false;
        for (auto q: graph[p]) {
            assert(P[q] == p);
            ok |= !contains[q];
        }
        if (ok) ans[i] = true;
    }
    cout << count(all(ans), 1) << endl;
}

int main() {
    int t = 1;
    //  cin >> t;
    while (t--) solve();
}