#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <map>
using namespace std;
int main() {
	int n;
	cin >> n;
	long long res = 0;
	for (int i = 1; i <= n; i++){
		if (i % 3 == 0 or i % 5 == 0) continue;
		res += i;
	}

	cout << res << endl;

}
