
import java.util.Scanner;

public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} import java.util.Scanner; Scanner java.util public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} Main static Scanner scanner; scanner public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	} main {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	} scanner = new Scanner(System.in) scanner new Scanner(System.in) int a=gi(); a gi() gi int b=gi(); b gi() gi int c=gi(); c gi() gi int d=gi(); d gi() gi int k=0; k 0 while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        } a>0&&c>0 a>0 a 0 c>0 c 0 {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        } if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	} k%2==1 k%2 k 2 1 {
        		a-=d;
        	} a-=d a d {
        		c-=b;
        	} c-=b c b k++ k if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        } a>0 a 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 static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	} d {
		String a=String.valueOf(n);
		return (long)a.length();
	} String a=String.valueOf(n); a String.valueOf(n) String.valueOf String n return (long)a.length(); (long)a.length() a.length a long n n // 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	} gs {
		return scanner.next();
	} return scanner.next(); scanner.next() scanner.next scanner // intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	} gi {
		return Integer.parseInt(scanner.next());
	} return Integer.parseInt(scanner.next()); Integer.parseInt(scanner.next()) Integer.parseInt Integer scanner.next() scanner.next scanner // longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	} gl {
		return Long.parseLong(scanner.next());
	} return Long.parseLong(scanner.next()); Long.parseLong(scanner.next()) Long.parseLong Long scanner.next() scanner.next scanner // doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	} gd {
		return Double.parseDouble(scanner.next());
	} return Double.parseDouble(scanner.next()); Double.parseDouble(scanner.next()) Double.parseDouble Double scanner.next() scanner.next scanner public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} Main

import java.util.Scanner;

public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int a=gi();
        int b=gi();
        int c=gi();
        int d=gi();
       
        int k=0;
        while(a>0&&c>0) {
        	if(k%2==1) {
        		a-=d;
        	}else {
        		c-=b;
        	}
        	k++;
        }

        //System.out.println();
        if (a>0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}