import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int Thp = scan.nextInt();
        int Tattack = scan.nextInt();
        int Ahp = scan.nextInt();
        int Aattack = scan.nextInt();
        while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    }
    }
} import java.util.Scanner; Scanner java.util class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int Thp = scan.nextInt();
        int Tattack = scan.nextInt();
        int Ahp = scan.nextInt();
        int Aattack = scan.nextInt();
        while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    }
    }
} Main public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int Thp = scan.nextInt();
        int Tattack = scan.nextInt();
        int Ahp = scan.nextInt();
        int Aattack = scan.nextInt();
        while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    }
    } main {
        Scanner scan = new Scanner(System.in);
        int Thp = scan.nextInt();
        int Tattack = scan.nextInt();
        int Ahp = scan.nextInt();
        int Aattack = scan.nextInt();
        while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int Thp = scan.nextInt(); Thp scan.nextInt() scan.nextInt scan int Tattack = scan.nextInt(); Tattack scan.nextInt() scan.nextInt scan int Ahp = scan.nextInt(); Ahp scan.nextInt() scan.nextInt scan int Aattack = scan.nextInt(); Aattack scan.nextInt() scan.nextInt scan while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    } true {
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    } if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             } (Ahp - Tattack) > 0 (Ahp - Tattack) Ahp Tattack 0 {
                Ahp = Ahp - Tattack;
             } Ahp = Ahp - Tattack Ahp Ahp - Tattack Ahp Tattack {
                 System.out.println("Yes");
                 break;     
             } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             } (Thp - Aattack) > 0 (Thp - Aattack) Thp Aattack 0 {
                 Thp = Thp - Aattack;
             } Thp = Thp - Aattack Thp Thp - Aattack Thp Aattack {
                 System.out.println("No");
                 break;
             } System.out.println("No") System.out.println System.out System System.out "No" break; String args[] args
import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int Thp = scan.nextInt();
        int Tattack = scan.nextInt();
        int Ahp = scan.nextInt();
        int Aattack = scan.nextInt();
        while(true){
            if((Ahp - Tattack) > 0){
                Ahp = Ahp - Tattack;
             }else{
                 System.out.println("Yes");
                 break;     
             }
             if((Thp - Aattack) > 0){
                 Thp = Thp - Aattack;
             }else{
                 System.out.println("No");
                 break;
             }
                    }
    }
}