#include <iostream>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>

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;
	return 0;
}
