#include <iostream>
#include <string>
#include <stdio.h>
#include <stdlib.h>

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";
	return 0;
}