import java.util.*;
import java.lang.Math;

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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	}
} import java.util.*; util.* java import java.lang.Math; Math java.lang 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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	}
} 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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	} main {
		Scanner sc = new Scanner(System.in);

  		
      	int a = sc.nextInt();
      	int b = sc.nextInt();
      	int c = sc.nextInt();
      	int d = sc.nextInt();
      	boolean twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	} 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 twin = false; twin false boolean awin = false; awin false String str = " "; str " " for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        } int i = 0; int i = 0; i 0 !twin && !awin !twin twin !awin awin i++ i++ i {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        } {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        } if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            } i % 2 == 0 i % 2 i 2 0 {
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } c -= b c b if(c <= 0) {
                twin = true;
              	str = "Yes";
              } c <= 0 c 0 {
                twin = true;
              	str = "Yes";
              } twin = true twin true str = "Yes" str "Yes" {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            } a -= d a d if(a <= 0) {
                awin = true;
                str = "No";
              } a <= 0 a 0 {
                awin = true;
                str = "No";
              } awin = true awin true str = "No" str "No" System.out.println(str) System.out.println System.out System System.out str 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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	}
} 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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	}
} Main
import java.util.*;
import java.lang.Math;

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 twin = false;
      	boolean awin = false;
      	String str = " ";
      
      	for(int i = 0;!twin && !awin;i++) {
			if(i % 2 == 0){
              c -= b;
              if(c <= 0) {
                twin = true;
              	str = "Yes";
              }
            } else {
              a -= d;
              if(a <= 0) {
                awin = true;
                str = "No";
              }
            }        
        }     	
      	
      	System.out.println(str);
        
	}
}
