import java.util.*;
class Main
{
  public static void main(String args[])
  {
    Scanner in=new Scanner(System.in);
    int a=in.nextInt();
     int b=in.nextInt();
     int c=in.nextInt();
     int d=in.nextInt();
    int flag=0;
    while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    }
    
      
      
      
    
    
    
    
  }
} import java.util.*; util.* java class Main
{
  public static void main(String args[])
  {
    Scanner in=new Scanner(System.in);
    int a=in.nextInt();
     int b=in.nextInt();
     int c=in.nextInt();
     int d=in.nextInt();
    int flag=0;
    while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    }
    
      
      
      
    
    
    
    
  }
} Main public static void main(String args[])
  {
    Scanner in=new Scanner(System.in);
    int a=in.nextInt();
     int b=in.nextInt();
     int c=in.nextInt();
     int d=in.nextInt();
    int flag=0;
    while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    }
    
      
      
      
    
    
    
    
  } main {
    Scanner in=new Scanner(System.in);
    int a=in.nextInt();
     int b=in.nextInt();
     int c=in.nextInt();
     int d=in.nextInt();
    int flag=0;
    while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    }
    
      
      
      
    
    
    
    
  } Scanner in=new Scanner(System.in); in new Scanner(System.in) int a=in.nextInt(); a in.nextInt() in.nextInt in int b=in.nextInt(); b in.nextInt() in.nextInt in int c=in.nextInt(); c in.nextInt() in.nextInt in int d=in.nextInt(); d in.nextInt() in.nextInt in int flag=0; flag 0 while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    } flag==0 flag 0 {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    } if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b; c-b<=0 c-b c b 0 {
         System.out.print("Yes");
         flag=1;
       } System.out.print("Yes") System.out.print System.out System System.out "Yes" flag=1 flag 1 c=c-b c c-b c b if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d; flag==0 && (a-d)<=0 flag==0 flag 0 (a-d)<=0 (a-d) a d 0 {
        flag=1;
        System.out.print("No");
      } flag=1 flag 1 System.out.print("No") System.out.print System.out System System.out "No" a=a-d a a-d a d String args[] args
import java.util.*;
class Main
{
  public static void main(String args[])
  {
    Scanner in=new Scanner(System.in);
    int a=in.nextInt();
     int b=in.nextInt();
     int c=in.nextInt();
     int d=in.nextInt();
    int flag=0;
    while(flag==0)
    {
       if(c-b<=0)
       {
         System.out.print("Yes");
         flag=1;
       }
       else
         c=c-b;
      if(flag==0 && (a-d)<=0)
      {
        flag=1;
        System.out.print("No");
      }
      else
        a=a-d;
    }
    
      
      
      
    
    
    
    
  }
}