import java.util.Scanner;

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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            System.out.println("No");
        }
    }
} import java.util.Scanner; Scanner 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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            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 double e=a*1.0/d; e a*1.0/d a*1.0 a 1.0 d int e1=a/d; e1 a/d a d if(e>e1){
            e1++;
        } e>e1 e e1 {
            e1++;
        } e1++ e1 double f=c*1.0/b; f c*1.0/b c*1.0 c 1.0 b int f1=c/b; f1 c/b c b if(f>f1){
            f1++;
        } f>f1 f f1 {
            f1++;
        } f1++ f1 if(e1>=f1){
           System.out.println("Yes");
       } e1>=f1 e1 f1 {
           System.out.println("Yes");
       } System.out.println("Yes") System.out.println System.out System System.out "Yes" if(e1<f1){
            System.out.println("No");
        } e1<f1 e1 f1 {
            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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            System.out.println("No");
        }
    }
} Main
import java.util.Scanner;

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();
        double e=a*1.0/d;
        int e1=a/d;
        if(e>e1){
            e1++;
        }
        double f=c*1.0/b;
        int f1=c/b;
        if(f>f1){
            f1++;
        }
       if(e1>=f1){
           System.out.println("Yes");
       }
        if(e1<f1){
            System.out.println("No");
        }
    }
}