#include <iostream>
#include <cstdlib>
#include <string>

using namespace std;

int main() {
  int n;
  scanf("%d", &n);

  long long sum = 0;
  for (int i = 1; i <= n; i++) {
    if ((i % 3 != 0) && (i % 5 != 0)) {
      sum += i;
    }
  }

  cout << sum << endl;
  return 0;
}
