#include<iostream>
#include <bits/stdc++.h>
#include <string>
#include <cstring>
#include <algorithm>
using namespace std;

int main() {
	
    int n  ;    
    cin >> n ;
    long long ans = 0 ;

    for (int i = 1;i<=n; i++){
        if(i%3==0 || i%5==0){
            continue ;
        }else{
            ans += i ;
        }
    }
    
    cout << ans << endl ;
    
  	return 0;
}
