import java.util.*;

public class Main{
    public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         }
} import java.util.*; util.* java public class Main{
    public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         }
} Main public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         } main {

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         } Scanner scn = new Scanner(System.in); scn new Scanner(System.in) int A = scn.nextInt(); A scn.nextInt() scn.nextInt scn int B = scn.nextInt(); B scn.nextInt() scn.nextInt scn int C = scn.nextInt(); C scn.nextInt() scn.nextInt scn int D = scn.nextInt(); D scn.nextInt() scn.nextInt scn while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      } A>0 || C>0 A>0 A 0 C>0 C 0 {
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      } C=C-B C C-B C B if(C<=0){
        System.out.println("Yes");
          break;
        } C<=0 C 0 {
        System.out.println("Yes");
          break;
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; A=A-D A A-D A D if(A<=0){
        System.out.println("No");
          break;
        } A<=0 A 0 {
        System.out.println("No");
          break;
        } System.out.println("No") System.out.println System.out System System.out "No" break; String args[] args public class Main{
    public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         }
} public class Main{
    public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         }
} Main
import java.util.*;

public class Main{
    public static void main(String args[]){

      Scanner scn = new Scanner(System.in);
      int A = scn.nextInt();
      int B = scn.nextInt();
      int C = scn.nextInt();
      int D = scn.nextInt();
      
      while(A>0 || C>0){
      C=C-B;
         if(C<=0){
        System.out.println("Yes");
          break;
        }
      A=A-D;
         if(A<=0){
        System.out.println("No");
          break;
        }
      }
         }
}