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

int main() {
  int N,S;
  S = 0;
  cin >> N;

  for (int i = 1; i < N+1; i++) {
    if (i%3 == 0 || i%5 == 0) {
    }
    else {
      S += i;
    }
  }
  cout << S << endl;
}
      