import java.io.*;

class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        String s[]=bu.readLine().split(" ");
        int a=Integer.parseInt(s[0]),b=Integer.parseInt(s[1]),c=Integer.parseInt(s[2]),d=Integer.parseInt(s[3]);
        int t=0;
        while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        }
        if(a>0) System.out.print("Yes");
        else System.out.print("No");
    }
} import java.io.*; io.* java class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        String s[]=bu.readLine().split(" ");
        int a=Integer.parseInt(s[0]),b=Integer.parseInt(s[1]),c=Integer.parseInt(s[2]),d=Integer.parseInt(s[3]);
        int t=0;
        while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        }
        if(a>0) System.out.print("Yes");
        else System.out.print("No");
    }
} Main public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        String s[]=bu.readLine().split(" ");
        int a=Integer.parseInt(s[0]),b=Integer.parseInt(s[1]),c=Integer.parseInt(s[2]),d=Integer.parseInt(s[3]);
        int t=0;
        while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        }
        if(a>0) System.out.print("Yes");
        else System.out.print("No");
    } main {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        String s[]=bu.readLine().split(" ");
        int a=Integer.parseInt(s[0]),b=Integer.parseInt(s[1]),c=Integer.parseInt(s[2]),d=Integer.parseInt(s[3]);
        int t=0;
        while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        }
        if(a>0) System.out.print("Yes");
        else System.out.print("No");
    } BufferedReader bu=new BufferedReader(new InputStreamReader(System.in)); bu new BufferedReader(new InputStreamReader(System.in)) String s[]=bu.readLine().split(" "); s bu.readLine().split(" ") bu.readLine().split bu.readLine() bu.readLine bu " " int a=Integer.parseInt(s[0]) a Integer.parseInt(s[0]) Integer.parseInt Integer s[0] s 0 b=Integer.parseInt(s[1]) b Integer.parseInt(s[1]) Integer.parseInt Integer s[1] s 1 c=Integer.parseInt(s[2]) c Integer.parseInt(s[2]) Integer.parseInt Integer s[2] s 2 d=Integer.parseInt(s[3]); d Integer.parseInt(s[3]) Integer.parseInt Integer s[3] s 3 int t=0; t 0 while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        } a>0 && c>0 a>0 a 0 c>0 c 0 {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        } if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;} t==1 t 1 {a-=d; t=0;} a-=d a d t=0 t 0 {t=1; c-=b;} t=1 t 1 c-=b c b if(a>0) System.out.print("Yes");
        else System.out.print("No"); a>0 a 0 System.out.print("Yes") System.out.print System.out System System.out "Yes" System.out.print("No") System.out.print System.out System System.out "No" String args[] args
import java.io.*;

class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        String s[]=bu.readLine().split(" ");
        int a=Integer.parseInt(s[0]),b=Integer.parseInt(s[1]),c=Integer.parseInt(s[2]),d=Integer.parseInt(s[3]);
        int t=0;
        while(a>0 && c>0)
        {
            if(t==1) {a-=d; t=0;}
            else {t=1; c-=b;}
        }
        if(a>0) System.out.print("Yes");
        else System.out.print("No");
    }
}
