import java.util.Scanner;

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();
   boolean flag=false;
   
   for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   }

   if(flag){
     System.out.println("Yes");
   }else{
     System.out.println("No");
   }
 
 }
} import java.util.Scanner; Scanner java.util 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();
   boolean flag=false;
   
   for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   }

   if(flag){
     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();
   boolean flag=false;
   
   for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   }

   if(flag){
     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();
   boolean flag=false;
   
   for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   }

   if(flag){
     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 boolean flag=false; flag false for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   } int i=0; int i=0; i 0 i++ i++ i {
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   } {
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   } c=c-b c c-b c b if(c<=0){
   flag=true;
   break;} c<=0 c 0 {
   flag=true;
   break;} flag=true flag true break; a=a-d a a-d a d if(a<=0){
   break;} a<=0 a 0 {
   break;} break; if(flag){
     System.out.println("Yes");
   }else{
     System.out.println("No");
   } flag {
     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
import java.util.Scanner;

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();
   boolean flag=false;
   
   for(int i=0;;i++){
   c=c-b;
   if(c<=0){
   flag=true;
   break;}
   a=a-d;
   if(a<=0){
   break;}
   }

   if(flag){
     System.out.println("Yes");
   }else{
     System.out.println("No");
   }
 
 }
}
