import java.util.Scanner;
//int[] date=new int[2];
public class Main {
int i,o,sum,h,s,e,u,ty,yu,ui,n,num,qw;
double m,t,r,j,k,f,d,g,w;
static double l;
String b,c,z,x,v,a,q;
Scanner scan =new Scanner(System.in);
//入力
	public void input() {	
	
	}
	//演算
	public void compute() {
	
		}
//出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		}
	public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		}
	} import java.util.Scanner; Scanner java.util public class Main {
int i,o,sum,h,s,e,u,ty,yu,ui,n,num,qw;
double m,t,r,j,k,f,d,g,w;
static double l;
String b,c,z,x,v,a,q;
Scanner scan =new Scanner(System.in);
//入力
	public void input() {	
	
	}
	//演算
	public void compute() {
	
		}
//出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		}
	public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		}
	} Main int i i o o sum sum h h s s e e u u ty ty yu yu ui ui n n num num qw; qw double m m t t r r j j k k f f d d g g w; w static double l; l String b b c c z z x x v v a a q; q Scanner scan =new Scanner(System.in); scan new Scanner(System.in) //入力
	public void input() {	
	
	} input {	
	
	} //演算
	public void compute() {
	
		} compute {
	
		} //出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		} output {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		} int[] date=new int[4]; date new int[4] 4 for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	} o=0; o=0 o 0 o<4 o 4 o++ o++ o {
		date[o]=scan.nextInt();
	} {
		date[o]=scan.nextInt();
	} date[o]=scan.nextInt() date[o] date o scan.nextInt() scan.nextInt scan while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
} true {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
} date[2]-=date[1] date[2] date 2 date[1] date 1 if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	} date[2]<=0 date[2] date 2 0 {
		System.out.println("Yes");
		break;
	} System.out.println("Yes") System.out.println System.out System System.out "Yes" break; {
		date[0]-=date[3];
	} date[0]-=date[3] date[0] date 0 date[3] date 3 if(date[0]<=0) {
		System.out.println("No");
		break;
	} date[0]<=0 date[0] date 0 0 {
		System.out.println("No");
		break;
	} System.out.println("No") System.out.println System.out System System.out "No" break; public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		} main {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		} Main p = new  Main (); p new  Main () p.input() p.input p p.compute() p.compute p p.output() p.output p String [ ] args args public class Main {
int i,o,sum,h,s,e,u,ty,yu,ui,n,num,qw;
double m,t,r,j,k,f,d,g,w;
static double l;
String b,c,z,x,v,a,q;
Scanner scan =new Scanner(System.in);
//入力
	public void input() {	
	
	}
	//演算
	public void compute() {
	
		}
//出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		}
	public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		}
	} public class Main {
int i,o,sum,h,s,e,u,ty,yu,ui,n,num,qw;
double m,t,r,j,k,f,d,g,w;
static double l;
String b,c,z,x,v,a,q;
Scanner scan =new Scanner(System.in);
//入力
	public void input() {	
	
	}
	//演算
	public void compute() {
	
		}
//出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		}
	public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		}
	} Main
import java.util.Scanner;
//int[] date=new int[2];
public class Main {
int i,o,sum,h,s,e,u,ty,yu,ui,n,num,qw;
double m,t,r,j,k,f,d,g,w;
static double l;
String b,c,z,x,v,a,q;
Scanner scan =new Scanner(System.in);
//入力
	public void input() {	
	
	}
	//演算
	public void compute() {
	
		}
//出力
	public void output() {
	int[] date=new int[4];
	for(o=0;o<4;o++) {
		date[o]=scan.nextInt();
	}
while(true) {
	date[2]-=date[1];
	if(date[2]<=0) {
		System.out.println("Yes");
		break;
	}else {
		date[0]-=date[3];
	}
	if(date[0]<=0) {
		System.out.println("No");
		break;
	}
}
		}
	public static void main(String [ ] args) {
		Main p = new  Main ();
		p.input();
		p.compute();
		p.output();
		}
	}