#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) {
    } else {
    	sum += i;
    }
  }
  cout << sum << endl;
}
