import java.util.*;

public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int hpA = sc.nextInt(); hpA sc.nextInt() sc.nextInt sc int atkA = sc.nextInt(); atkA sc.nextInt() sc.nextInt sc int hpB = sc.nextInt(); hpB sc.nextInt() sc.nextInt sc int atkB = sc.nextInt(); atkB sc.nextInt() sc.nextInt sc boolean turn = true; turn true while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        } turn {
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        } hpB -= atkA hpB atkA if(hpB <= 0) break; hpB <= 0 hpB 0 break; hpA -= atkB hpA atkB if(hpA <= 0) break; hpA <= 0 hpA 0 break; if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } hpA > hpB hpA hpB {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } 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 Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
        int hpA = sc.nextInt();
        int atkA = sc.nextInt();
        int hpB = sc.nextInt();
        int atkB = sc.nextInt();

        boolean turn = true;
        while(turn){
            hpB -= atkA;
            if(hpB <= 0) break;
            hpA -= atkB;
            if(hpA <= 0) break;
        }
        if(hpA > hpB){
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}