import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	}
	 
	
}	
 import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	}
	 
	
} Main public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	} main {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	} BufferedReader bw = new BufferedReader(new InputStreamReader(System.in)); bw new BufferedReader(new InputStreamReader(System.in)) String s = bw.readLine(); s bw.readLine() bw.readLine bw String[] w = s.split("\\s+"); w s.split("\\s+") s.split s "\\s+" int healthA = Integer.parseInt(w[0]); healthA Integer.parseInt(w[0]) Integer.parseInt Integer w[0] w 0 int attackA = Integer.parseInt(w[1]); attackA Integer.parseInt(w[1]) Integer.parseInt Integer w[1] w 1 int healthB = Integer.parseInt(w[2]); healthB Integer.parseInt(w[2]) Integer.parseInt Integer w[2] w 2 int attackB = Integer.parseInt(w[3]); attackB Integer.parseInt(w[3]) Integer.parseInt Integer w[3] w 3 int bitTimesA = healthA/attackB; bitTimesA healthA/attackB healthA attackB bitTimesA+=(healthA%attackB)==0?0:1 bitTimesA (healthA%attackB)==0?0:1 (healthA%attackB)==0 (healthA%attackB) healthA attackB 0 0 1 int bitTimesB = healthB/attackA; bitTimesB healthB/attackA healthB attackA bitTimesB+=(healthB%attackA)==0?0:1 bitTimesB (healthB%attackA)==0?0:1 (healthB%attackA)==0 (healthB%attackA) healthB attackA 0 0 1 if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		} bitTimesA >= bitTimesB bitTimesA bitTimesB {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" if( bitTimesA < bitTimesB) {
			System.out.println("No");
		} bitTimesA < bitTimesB bitTimesA bitTimesB {
			System.out.println("No");
		} System.out.println("No") System.out.println System.out System System.out "No" bw.close() bw.close bw String[] args args public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	}
	 
	
} public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	}
	 
	
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader bw = new BufferedReader(new InputStreamReader(System.in));
		String s = bw.readLine();
		String[] w = s.split("\\s+");
		int healthA = Integer.parseInt(w[0]);
		int attackA = Integer.parseInt(w[1]);
		int healthB = Integer.parseInt(w[2]);
		int attackB = Integer.parseInt(w[3]); 
		
		int bitTimesA = healthA/attackB;
		bitTimesA+=(healthA%attackB)==0?0:1;
		int bitTimesB = healthB/attackA;
		bitTimesB+=(healthB%attackA)==0?0:1;
		
		if( bitTimesA >= bitTimesB) {
			System.out.println("Yes");
		}
		else if( bitTimesA < bitTimesB) {
			System.out.println("No");
		}
		
		bw.close();
	}
	 
	
}	

