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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    }
} 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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    }
} 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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    } 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 cntT = c / b; cntT c / b c b if(c % b != 0) cntT++; c % b != 0 c % b c b 0 cntT++ cntT int cntA = a / d; cntA a / d a d if(a % d != 0) cntA++; a % d != 0 a % d a d 0 cntA++ cntA System.out.println( cntT <= cntA ? "Yes" : "No") System.out.println System.out System System.out cntT <= cntA ? "Yes" : "No" cntT <= cntA cntT cntA "Yes" "No" 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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    }
} 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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    }
} Main
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 cntT = c / b;
        if(c % b != 0) cntT++;
        int cntA = a / d;
        if(a % d != 0) cntA++;
        System.out.println( cntT <= cntA ? "Yes" : "No");
    }
}