#include <bits/stdc++.h>
using namespace std;
int main() {
    int n; cin >> n;
    long long counter = 0;
    for (int i = 1; i <= n; i++) {
        if (i % 3 != 0  && i % 5 != 0)
            counter += i;
    }
    cout << counter << endl;
    return 0;
}
