#include <iostream>
using namespace std;
int main(int argc, char const *argv[]) {
  double n;
  int sum=0;
  cin>>n;
  for(int i=1;i<=n;i++){
    if(i%3!=0&&i%5!=0){
      sum+=i;
    }
  }
  cout<<sum<<endl;
  return 0;
}