#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
 
int main(){
  
  ll N;
  cin >> N;
  
  ll ans = 0;
  for(int i = 1;i <= N;++i){
    if(i % 3 != 0 && i % 5 != 0)  ans += i;
  }
  
  cout << ans << endl;
  
  return 0;
}