Untitled

import java.util.Scanner;
import java.lang.Math; 
 
public class Main {
 
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        long m = 5 * n * n + 4;
        long p = 5 * n * n - 4;
        double msq = Math.ceil(Math.sqrt(m));
        double psq = Math.ceil(Math.sqrt(p));
        if (m / msq == msq)
            System.out.println("YES");
        else if (p / psq == psq)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}