import java.util.Scanner;

public class Main {//Risolto in =(1)
    public static long sum(long n) {
        return n * (n + 1) / 2;
    }

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

        long res = sum(n) - sum(n/3) * 3 - sum(n / 5) * 5 + sum(n / 15) * 15;

        System.out.print(res);
    }
}

/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