
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	} main {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Integer tHP = sc.nextInt(); tHP sc.nextInt() sc.nextInt sc Integer tAT = sc.nextInt(); tAT sc.nextInt() sc.nextInt sc Integer aHP = sc.nextInt(); aHP sc.nextInt() sc.nextInt sc Integer aAT = sc.nextInt(); aAT sc.nextInt() sc.nextInt sc while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		} tHP > 0 && aHP > 0 tHP > 0 tHP 0 aHP > 0 aHP 0 {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		} aHP = aHP - tAT aHP aHP - tAT aHP tAT tHP = tHP - aAT tHP tHP - aAT tHP aAT if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		} aHP <= 0 aHP 0 {
			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);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
} Main

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Integer tHP = sc.nextInt();
		Integer tAT = sc.nextInt();
		Integer aHP = sc.nextInt();
		Integer aAT = sc.nextInt();

		while(tHP > 0 && aHP > 0) {
			aHP = aHP - tAT;
			tHP = tHP - aAT;
		}
		
		if(aHP <= 0) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}
}
