import java.util.*;
 
 
class Main {
 
    public static void main (String args[])
    {
        Scanner in = new Scanner(System.in);
       
        int th = in.nextInt();
        int as=in.nextInt();
        int tth = in.nextInt();
        int aas=in.nextInt();
        
        while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.*; util.* java class Main {
 
    public static void main (String args[])
    {
        Scanner in = new Scanner(System.in);
       
        int th = in.nextInt();
        int as=in.nextInt();
        int tth = in.nextInt();
        int aas=in.nextInt();
        
        while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        }
    }
} Main public static void main (String args[])
    {
        Scanner in = new Scanner(System.in);
       
        int th = in.nextInt();
        int as=in.nextInt();
        int tth = in.nextInt();
        int aas=in.nextInt();
        
        while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner in = new Scanner(System.in);
       
        int th = in.nextInt();
        int as=in.nextInt();
        int tth = in.nextInt();
        int aas=in.nextInt();
        
        while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        }
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) int th = in.nextInt(); th in.nextInt() in.nextInt in int as=in.nextInt(); as in.nextInt() in.nextInt in int tth = in.nextInt(); tth in.nextInt() in.nextInt in int aas=in.nextInt(); aas in.nextInt() in.nextInt in while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        } th>0 th 0 {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        } tth-=as tth as if(tth<=0)
            {
                System.out.println("Yes");
                break;
            } tth<=0 tth 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; th-=aas th aas if(th<=0)
            {
                System.out.println("No");
                break;
            } th<=0 th 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String args[] args
import java.util.*;
 
 
class Main {
 
    public static void main (String args[])
    {
        Scanner in = new Scanner(System.in);
       
        int th = in.nextInt();
        int as=in.nextInt();
        int tth = in.nextInt();
        int aas=in.nextInt();
        
        while(th>0)
        {   
            tth-=as;
            if(tth<=0)
            {
                System.out.println("Yes");
                break;
            }
            th-=aas;
            if(th<=0)
            {
                System.out.println("No");
                break;
            }
        }
    }
}