import java.util.*;
 
public class Main{
  
  public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  }
  
} import java.util.*; util.* java public class Main{
  
  public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  }
  
} Main public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  } main {
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int tH = sc.nextInt(); tH sc.nextInt() sc.nextInt sc int tA = sc.nextInt(); tA sc.nextInt() sc.nextInt sc int aH = sc.nextInt(); aH sc.nextInt() sc.nextInt sc int aA = sc.nextInt(); aA sc.nextInt() sc.nextInt sc int tCount =0; tCount 0 while(tH > 0){ 
     tH -= aA;
     tCount++;
    } tH > 0 tH 0 { 
     tH -= aA;
     tCount++;
    } tH -= aA tH aA tCount++ tCount int aCount =0; aCount 0 while(aH > 0){ 
      aH -= tA;
      aCount++;
    } aH > 0 aH 0 { 
      aH -= tA;
      aCount++;
    } aH -= tA aH tA aCount++ aCount if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    } tCount < aCount tCount aCount {
      System.out.println("No");
    } System.out.println("No") System.out.println System.out System System.out "No" if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    } tCount == aCount tCount aCount {
      System.out.println("Yes");
    } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
       System.out.println("Yes");
    } System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main{
  
  public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  }
  
} public class Main{
  
  public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  }
  
} Main
import java.util.*;
 
public class Main{
  
  public static void main(String[] args){
   
    Scanner sc = new Scanner(System.in);
    
    int tH = sc.nextInt();
    int tA = sc.nextInt();
    int aH = sc.nextInt();
    int aA = sc.nextInt();
   
    int tCount =0;
    while(tH > 0){ 
     tH -= aA;
     tCount++;
    }
     
    int aCount =0;
    while(aH > 0){ 
      aH -= tA;
      aCount++;
    }
    
    if(tCount < aCount){
      System.out.println("No");
    }else if(tCount == aCount){
      System.out.println("Yes");
    }else{
       System.out.println("Yes");
    }
   
  }
  
}