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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0; t 0 int ao = 0; ao 0 for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
} int i=0; int i=0; i 0 i<100 i 100 i++ i++ i {
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
} {
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
} if(c-b*i>0){
        t++;
        } c-b*i>0 c-b*i c b*i b i 0 {
        t++;
        } t++ t if(a-d*i>0){
        ao++;
    } a-d*i>0 a-d*i a d*i d i 0 {
        ao++;
    } ao++ ao if(t<=ao){
       	System.out.println("Yes");
        }else{
        System.out.println("No");
    } t<=ao t 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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=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 t = 0;
    int ao = 0;
    for(int i=0; i<100; i++){
    if(c-b*i>0){
        t++;
        }
    if(a-d*i>0){
        ao++;
    }
}
        if(t<=ao){
       	System.out.println("Yes");
        }else{
        System.out.println("No");
    }
}
}
