import java.util.*;
public class Main{
	
	public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}
} import java.util.*; util.* java public class Main{
	
	public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}
} Main public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	} main {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	} Scanner s = new Scanner(System.in); s new Scanner(System.in) int a = s.nextInt(); a s.nextInt() s.nextInt s int b = s.nextInt(); b s.nextInt() s.nextInt s int c = s.nextInt(); c s.nextInt() s.nextInt s int d = s.nextInt(); d s.nextInt() s.nextInt s int flag = 0; flag 0 while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        } true {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        } if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	} a <= 0 || c <= 0 a <= 0 a 0 c <= 0 c 0 {
        		break;
        	} break; {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	} if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		} flag == 0 flag 0 {
        			c -= b;
        			flag = 1;
        		} c -= b c b flag = 1 flag 1 {
        			a -= d;
        			flag = 0;
        		} a -= d a d flag = 0 flag 0 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 class Main{
	
	public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}
} public class Main{
	
	public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}
} Main
import java.util.*;
public class Main{
	
	public static void main(String args[]) {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int b = s.nextInt();
        int c = s.nextInt();
        int d = s.nextInt();
        int flag = 0;
        while(true) {
        	if(a <= 0 || c <= 0) {
        		break;
        	}else {
        		if(flag == 0) {
        			c -= b;
        			flag = 1;
        		}else {
        			a -= d;
        			flag = 0;
        		}
        	}
        }
        if(a > 0) {
        	System.out.println("Yes");
        }else {
        	System.out.println("No");
        }
	}
}