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