#include <bits/stdc++.h>
using namespace std;

int main(){
  int64_t N;
  cin >> N;
  int64_t ans=0;
  for(int i=1;i<=N;i++){
    if((i%3!=0)&&(i%5!=0)){
      ans+=i;
    }
  }
  cout << ans << endl;
  return 0;
}
