#include<iostream>

using namespace std;

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

		}
	}
	cout << sum << "\n";
}