#include <bits/stdc++.h>
using namespace std;
using ll = long long;
 
int main() {
cout<<fixed<<setprecision(10);

  ll N;
  cin >>N;
  ll sum=0;
  for (int i=1; i<N; i++){
  	if (i%3!=0 && i%5!=0) sum += i;
  
  }
  cout <<sum;

	
}