import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    } main {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int aHealth = sc.nextInt(); aHealth sc.nextInt() sc.nextInt sc int aAttack = sc.nextInt(); aAttack sc.nextInt() sc.nextInt sc int bHealth = sc.nextInt(); bHealth sc.nextInt() sc.nextInt sc int bAttack = sc.nextInt(); bAttack sc.nextInt() sc.nextInt sc int aWin = (int) Math.ceil((double) bHealth/aAttack); aWin (int) Math.ceil((double) bHealth/aAttack) Math.ceil Math (double) bHealth/aAttack (double) bHealth aAttack int bWin = (int) Math.ceil((double) aHealth/bAttack); bWin (int) Math.ceil((double) aHealth/bAttack) Math.ceil Math (double) aHealth/bAttack (double) aHealth bAttack System.out.println(aWin <= bWin ? "Yes" : "No") System.out.println System.out System System.out aWin <= bWin ? "Yes" : "No" aWin <= bWin aWin bWin "Yes" "No" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int aHealth = sc.nextInt();
        int aAttack = sc.nextInt();
        int bHealth = sc.nextInt();
        int bAttack = sc.nextInt();
        int aWin = (int) Math.ceil((double) bHealth/aAttack);
        int bWin = (int) Math.ceil((double) aHealth/bAttack);
        System.out.println(aWin <= bWin ? "Yes" : "No");
    }
}
