#include <iostream>
using namespace std;
int main() {
    int n;
    cin >> n;
    long long ans = 0;
    for (int i = 1; i <= n; ++i) {
        if (i % 3 == 0 || i % 5 == 0)
            continue;
        ans += i;
    }
    cout << ans << endl;
    return 0;
}
