#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<stack>
#include<set>

using namespace std;

long long x = 1000000007;


int main() {
	int n;
	cin >> n;
	long long ans = 0;
	for (int i = 1; i <= n; i++) {
		if (i % 3 != 0 && i % 5 != 0)ans += i;
	}
	cout << ans << endl;
	return 0;
}