#include <bits/stdc++.h>
using namespace std ;
 
int main() {
  
 int n ; 
 cin >> n;  
 long long sum = 0 ; 

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

