import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long H = sc.nextLong();
		long W = sc.nextLong();
		long N = sc.nextLong();
		long K = sc.nextLong();

		H %= N;
		W %= N;

		long all = H * N;
		all %= N;
		if(all==K){
			System.out.println("YES");
		}else {
			System.out.println("NO");
			
		}

	}
}