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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         System.out.println("Yes");
      }else{
         System.out.println("No");
      }
	}
} 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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         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 int cnt1 = 0; cnt1 0 int cnt2 = 0; cnt2 0 while(a>0){
         cnt1++;
         a-=d;
      } a>0 a 0 {
         cnt1++;
         a-=d;
      } cnt1++ cnt1 a-=d a d while(c>0){
         cnt2++;
         c-=b;
      } c>0 c 0 {
         cnt2++;
         c-=b;
      } cnt2++ cnt2 c-=b c b if(cnt1>=cnt2){
         System.out.println("Yes");
      }else{
         System.out.println("No");
      } cnt1>=cnt2 cnt1 cnt2 {
         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 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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         System.out.println("Yes");
      }else{
         System.out.println("No");
      }
	}
} 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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         System.out.println("Yes");
      }else{
         System.out.println("No");
      }
	}
} 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();
      int cnt1 = 0;
      int cnt2 = 0;
      while(a>0){
         cnt1++;
         a-=d;
      }
      while(c>0){
         cnt2++;
         c-=b;
      }
      if(cnt1>=cnt2){
         System.out.println("Yes");
      }else{
         System.out.println("No");
      }
	}
}
