#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>
#include <vector>

using namespace std;

int main(){
	int N;
	cin >> N;

	long long sum = 0;
	for (int i = 1; i <= N; i++)
	{
		/* code */
		if(i % 3 != 0 && i % 5 != 0){
			sum += i;
		}
	}
	cout << sum << endl;
}