import java.util.*;

public 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 takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      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 a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
      boolean takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes");
	}
} 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 takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes");
	} main {
	Scanner sc = new Scanner(System.in);
	int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
      boolean takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes");
	} 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 takahashi = true; takahashi true while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      } a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      } if(takahashi)
          c -= b;
        else
          a -= d; takahashi c -= b c b a -= d a d takahashi = !takahashi takahashi !takahashi takahashi if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes"); takahashi System.out.println("No") System.out.println System.out System System.out "No" 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 a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
      boolean takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes");
	}
} public 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 takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      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 a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
      boolean takahashi = true;
      while(a > 0 && c > 0){
        if(takahashi)
          c -= b;
        else
          a -= d;
        takahashi = !takahashi;    
      }
      if(takahashi)
        System.out.println("No");
      else
        System.out.println("Yes");
	}
}