#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#define rep(i,n) for(int i = 0; i < (n); ++i)
using ll = long long;
using namespace std;
int main()
{
	int n;
	cin >> n;
	ll ans = 0;
	rep(i, n + 1) {
		if (i % 3 != 0 && i % 5 != 0)	ans += i;
	}
	cout << ans << endl;
	return 0;
}