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