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

int main() {
  int n, sum = 0;
  cin >> n;
  
  for(int i = 1; i <= n; i++){
    if(i % 3 == 0 || i % 5 == 0)
      continue;
    else
      sum += i;
  }
  
  cout << sum << endl;
  
}
