import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    }
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    } main {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    } Scanner sc = new Scanner (System.in); sc new Scanner (System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int c = sc.nextInt(); c sc.nextInt() sc.nextInt sc int d = sc.nextInt(); d sc.nextInt() sc.nextInt sc int count = a/d; count a/d a d int s = c/b; s c/b c b if(a%d!=0) count++; a%d!=0 a%d a d 0 count++ count if(c%b!=0) s++; c%b!=0 c%b c b 0 s++ s if(s>count) System.out.println("No");
        else System.out.println("Yes"); s>count s count System.out.println("No") System.out.println System.out System System.out "No" System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    }
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner (System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int count = a/d;
        int s = c/b;
        if(a%d!=0) count++;
        if(c%b!=0) s++;
        if(s>count) System.out.println("No");
        else System.out.println("Yes");
    }
}