import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    } 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 for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        } ; {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        } {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        } c -= b c b if(c <= 0){
                System.out.println("Yes");
                return;
            } c <= 0 c 0 {
                System.out.println("Yes");
                return;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" return; a -= d a d if(a <= 0){
                System.out.println("No");
                return;
            } a <= 0 a 0 {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // 整数の入力
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();

        for(;;) {
            c -= b;
            if(c <= 0){
                System.out.println("Yes");
                return;
            }
            a -= d;
            if(a <= 0){
                System.out.println("No");
                return;
            }
        }
    }
}
