#include <iostream>
#include <string>
using namespace std;

int main() {
	long long n,s=0;
	cin >> n;
	for (long long i = 0; i <= n; ++i) {
		if (i % 3 == 0 || i % 5 == 0) {
			
		}
		else {
			s += i;
		}
	}
	cout << s << endl;
	return 0;
}
