import java.io.*;
import java.util.*;
public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   }
} import java.io.*; io.* java import java.util.*; util.* java public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   }
} Main public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   } main {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st = new StringTokenizer(br.readLine()); st new StringTokenizer(br.readLine()) int h1 = Integer.parseInt(st.nextToken()); h1 Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int s1 = Integer.parseInt(st.nextToken()); s1 Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int h2 = Integer.parseInt(st.nextToken()); h2 Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int s2 = Integer.parseInt(st.nextToken()); s2 Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int t1 = (h2%s1==0?h2/s1:h2/s1+1); t1 (h2%s1==0?h2/s1:h2/s1+1) h2%s1==0 h2%s1 h2 s1 0 h2/s1 h2 s1 h2/s1+1 h2/s1 h2 s1 1 int t2 = (h1%s2==0?h1/s2:h1/s2+1); t2 (h1%s2==0?h1/s2:h1/s2+1) h1%s2==0 h1%s2 h1 s2 0 h1/s2 h1 s2 h1/s2+1 h1/s2 h1 s2 1 if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No"); t1<=t2 t1 t2 System.out.println("Yes") System.out.println System.out System System.out "Yes" 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[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   }
} public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   }
} Main
import java.io.*;
import java.util.*;
public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   StringTokenizer st = new StringTokenizer(br.readLine());
   int h1 = Integer.parseInt(st.nextToken());
   int s1 = Integer.parseInt(st.nextToken());
   int h2 = Integer.parseInt(st.nextToken());
   int s2 = Integer.parseInt(st.nextToken());
   int t1 = (h2%s1==0?h2/s1:h2/s1+1);
   int t2 = (h1%s2==0?h1/s2:h1/s2+1);
   if(t1<=t2)
   	System.out.println("Yes");
   else
   		System.out.println("No");
   }
}
