#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)
#define VSORT(v) sort(v.begin(), v.end())
#define ALL(a) (a).begin(),(a).end()

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    vector<int> a(n);
    REP(i, n) cin >> a[i];
    VSORT(a);

    int ans = 0;
    REP(i, n) {
        while (a[i] == a[i + 1]) i++;
        if (upper_bound(ALL(a), a[i]) - lower_bound(ALL(a), a[i]) == 1) ans++;
    }
    cout << ans << endl;
    return 0;
}