
import java.util.*;

public class Main {

	public static void main(String[] args) {
		Main main = new Main();
		main.run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long ans = 0;
		for(long i=1; i<=n; i++) {
			if(i%3==0||i%5==0) continue;
			ans += i;
		}
		System.out.println(ans);
		sc.close();
	}


}
