import java.util.*;
class Main
{
    public static void main(String args[])
    {
        Scanner ob=new Scanner(System.in);
        int ah=ob.nextInt();int as=ob.nextInt();
        int bh=ob.nextInt();int bs=ob.nextInt();
        int tak=(int)Math.ceil((double)bh/as);
        int akoi=(int)Math.ceil((double)ah/bs);
        System.out.println(tak<=akoi?"Yes":"No");
    }
} import java.util.*; util.* java class Main
{
    public static void main(String args[])
    {
        Scanner ob=new Scanner(System.in);
        int ah=ob.nextInt();int as=ob.nextInt();
        int bh=ob.nextInt();int bs=ob.nextInt();
        int tak=(int)Math.ceil((double)bh/as);
        int akoi=(int)Math.ceil((double)ah/bs);
        System.out.println(tak<=akoi?"Yes":"No");
    }
} Main public static void main(String args[])
    {
        Scanner ob=new Scanner(System.in);
        int ah=ob.nextInt();int as=ob.nextInt();
        int bh=ob.nextInt();int bs=ob.nextInt();
        int tak=(int)Math.ceil((double)bh/as);
        int akoi=(int)Math.ceil((double)ah/bs);
        System.out.println(tak<=akoi?"Yes":"No");
    } main {
        Scanner ob=new Scanner(System.in);
        int ah=ob.nextInt();int as=ob.nextInt();
        int bh=ob.nextInt();int bs=ob.nextInt();
        int tak=(int)Math.ceil((double)bh/as);
        int akoi=(int)Math.ceil((double)ah/bs);
        System.out.println(tak<=akoi?"Yes":"No");
    } Scanner ob=new Scanner(System.in); ob new Scanner(System.in) int ah=ob.nextInt(); ah ob.nextInt() ob.nextInt ob int as=ob.nextInt(); as ob.nextInt() ob.nextInt ob int bh=ob.nextInt(); bh ob.nextInt() ob.nextInt ob int bs=ob.nextInt(); bs ob.nextInt() ob.nextInt ob int tak=(int)Math.ceil((double)bh/as); tak (int)Math.ceil((double)bh/as) Math.ceil Math (double)bh/as (double)bh as int akoi=(int)Math.ceil((double)ah/bs); akoi (int)Math.ceil((double)ah/bs) Math.ceil Math (double)ah/bs (double)ah bs System.out.println(tak<=akoi?"Yes":"No") System.out.println System.out System System.out tak<=akoi?"Yes":"No" tak<=akoi tak akoi "Yes" "No" String args[] args
import java.util.*;
class Main
{
    public static void main(String args[])
    {
        Scanner ob=new Scanner(System.in);
        int ah=ob.nextInt();int as=ob.nextInt();
        int bh=ob.nextInt();int bs=ob.nextInt();
        int tak=(int)Math.ceil((double)bh/as);
        int akoi=(int)Math.ceil((double)ah/bs);
        System.out.println(tak<=akoi?"Yes":"No");
    }
}