#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <iomanip>
#include <cmath>

using namespace std;
typedef long long ll;

#define cout (cout << setprecision(12))

int main() {
    int N;
    cin >> N;
    ll ans = 0;
    for (int i = 1; i <= N; i++) {
        if (i % 3 != 0 && i % 5 != 0) ans += i;
    }
    cout << ans << endl;
}