import java.util.*;
class Main{
 static public void main(String args[]){
  Scanner sc=new Scanner(System.in); 
   boolean flag;
   int a,b,c,d;
   a=sc.nextInt();
   b=sc.nextInt();//kougeki
   c=sc.nextInt();
   d=sc.nextInt();//kougeki
   
   while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   }
   
   if(flag)System.out.println("Yes");
   else System.out.println("No");
 }
} import java.util.*; util.* java class Main{
 static public void main(String args[]){
  Scanner sc=new Scanner(System.in); 
   boolean flag;
   int a,b,c,d;
   a=sc.nextInt();
   b=sc.nextInt();//kougeki
   c=sc.nextInt();
   d=sc.nextInt();//kougeki
   
   while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   }
   
   if(flag)System.out.println("Yes");
   else System.out.println("No");
 }
} Main static public void main(String args[]){
  Scanner sc=new Scanner(System.in); 
   boolean flag;
   int a,b,c,d;
   a=sc.nextInt();
   b=sc.nextInt();//kougeki
   c=sc.nextInt();
   d=sc.nextInt();//kougeki
   
   while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   }
   
   if(flag)System.out.println("Yes");
   else System.out.println("No");
 } main {
  Scanner sc=new Scanner(System.in); 
   boolean flag;
   int a,b,c,d;
   a=sc.nextInt();
   b=sc.nextInt();//kougeki
   c=sc.nextInt();
   d=sc.nextInt();//kougeki
   
   while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   }
   
   if(flag)System.out.println("Yes");
   else System.out.println("No");
 } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) boolean flag; flag int a a b b c c d; d a=sc.nextInt() a sc.nextInt() sc.nextInt sc b=sc.nextInt() b sc.nextInt() sc.nextInt sc c=sc.nextInt() c sc.nextInt() sc.nextInt sc d=sc.nextInt() d sc.nextInt() sc.nextInt sc while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   } true {
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   } c-=b c b if(c<=0){
	 	flag=true;break;
		} c<=0 c 0 {
	 	flag=true;break;
		} flag=true flag true break; a-=d a d if(a<=0){
	 	flag=false;break;
		}
		
	 else continue; a<=0 a 0 {
	 	flag=false;break;
		} flag=false flag false break; continue; if(flag)System.out.println("Yes");
   else System.out.println("No"); flag System.out.println("Yes") System.out.println System.out System System.out "Yes" System.out.println("No") System.out.println System.out System System.out "No" String args[] args
import java.util.*;
class Main{
 static public void main(String args[]){
  Scanner sc=new Scanner(System.in); 
   boolean flag;
   int a,b,c,d;
   a=sc.nextInt();
   b=sc.nextInt();//kougeki
   c=sc.nextInt();
   d=sc.nextInt();//kougeki
   
   while(true){
  	
     c-=b;
	 
	 	if(c<=0){
	 	flag=true;break;
		}

	 a-=d;
	    if(a<=0){
	 	flag=false;break;
		}
		
	 else continue;
   }
   
   if(flag)System.out.println("Yes");
   else System.out.println("No");
 }
}