#include <iostream>
using namespace std;

int main() {
    int n;
    cin>>n;

    unsigned long long ans = 0;
    for (int i=1; i<=n; i++) {
        if (0==i%3 || 0==i%5) {
            continue;
        }
        ans += i;
    }

    cout << ans << endl;

    return 0;
}