import java.util.Scanner;

class Main {
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    sc.close();

    long p = 1;
    long sum = 0;
    for (int i = 0; i < n; i++) {
      if (p%5 == 0 || p%3 == 0) {
        p++;
        continue;
      } else {
        sum += p;
        p++;
      }
    }
    System.out.println(sum);
  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz