import java.util.*;


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

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int t_life = sc.nextInt(); t_life sc.nextInt() sc.nextInt sc int t_attack = sc.nextInt(); t_attack sc.nextInt() sc.nextInt sc int a_life = sc.nextInt(); a_life sc.nextInt() sc.nextInt sc int a_attack = sc.nextInt(); a_attack sc.nextInt() sc.nextInt sc int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1; ans1 a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1 a_life % t_attack == 0 a_life % t_attack a_life t_attack 0 a_life / t_attack a_life t_attack (a_life / t_attack) + 1 (a_life / t_attack) a_life t_attack 1 int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1; ans2 t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1 t_life % a_attack == 0 t_life % a_attack t_life a_attack 0 t_life / a_attack t_life a_attack (t_life / a_attack) + 1 (t_life / a_attack) t_life a_attack 1 if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } ans1 <= ans2 ans1 ans2 {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.*;


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

        int t_life = sc.nextInt();
        int t_attack = sc.nextInt();
        int a_life = sc.nextInt();
        int a_attack = sc.nextInt();

        int ans1 = a_life % t_attack == 0 ? a_life / t_attack : (a_life / t_attack) + 1;
        int ans2 = t_life % a_attack == 0 ? t_life / a_attack : (t_life / a_attack) + 1;

        if (ans1 <= ans2) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}