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

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