import java.util.Scanner;
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 i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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);
	int A=sc.nextInt();
	int B=sc.nextInt();
	int C=sc.nextInt();
	int D=sc.nextInt();
	int i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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 i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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 i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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 i=0; i 0 int j=0; j 0 for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	} ; {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	} {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	} i++ i C-=B C B if(C<=0) {
			break;
		} C<=0 C 0 {
			break;
		} break; for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	} ; {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	} {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	} j++ j A-=D A D if(A<=0) {
			break;
		} A<=0 A 0 {
			break;
		} break; if(i<=j) {
		System.out.println("Yes");
	}
	else {
		System.out.println("No");
	} i<=j i j {
		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 i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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 i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		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);
	int A=sc.nextInt();
	int B=sc.nextInt();
	int C=sc.nextInt();
	int D=sc.nextInt();
	int i=0;
	int j=0;
	for(;;) {
		i++;
		C-=B;
		if(C<=0) {
			break;
		}
	}
	for(;;) {
		j++;
		A-=D;
		if(A<=0) {
			break;
		}
	}
	if(i<=j) {
		System.out.println("Yes");
	}
	else {
		System.out.println("No");
	}
	}
}