import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            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 a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a =sc.nextInt(); a sc.nextInt() sc.nextInt sc int b =sc.nextInt(); b sc.nextInt() sc.nextInt sc int c =sc.nextInt(); c sc.nextInt() sc.nextInt sc int d =sc.nextInt(); d sc.nextInt() sc.nextInt sc int taka = c / b; taka c / b c b if (c % b != 0) {
            taka++;
        } c % b != 0 c % b c b 0 {
            taka++;
        } taka++ taka int ao = a / d; ao a / d a d if (a % d != 0) {
            ao++;
        } a % d != 0 a % d a d 0 {
            ao++;
        } ao++ ao if (taka <= ao) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } taka <= ao taka ao {
            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 a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            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 a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            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 a =sc.nextInt();
        int b =sc.nextInt();
        int c =sc.nextInt();
        int d =sc.nextInt();
        int taka = c / b;
        if (c % b != 0) {
            taka++;
        }
        int ao = a / d;
        if (a % d != 0) {
            ao++;
        }
        
        if (taka <= ao) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}