#include<iostream>
#include<algorithm>
#include <vector>

using namespace std;


int main() {
	long long n;
	long long count = 0;

	cin >> n;
	for (long long i = 1; i <= n; i++) {
		if (i % 3 != 0 && i % 5 != 0) {
			count += i;
		}
	}

	cout << count;

}
