import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt() a sc.nextInt() sc.nextInt sc b = sc.nextInt() b sc.nextInt() sc.nextInt sc c = sc.nextInt() c sc.nextInt() sc.nextInt sc d = sc.nextInt() d sc.nextInt() sc.nextInt sc z = 0; z 0 while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        } true {
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        } c -= b c b a -= d a d if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            } c <= 0 c 0 {
                System.out.println("Yes");
                System.exit(0);
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" System.exit(0) System.exit System 0 if(a <= 0){
                System.out.println("No");
                System.exit(0);
            } a <= 0 a 0 {
                System.out.println("No");
                System.exit(0);
            } System.out.println("No") System.out.println System.out System System.out "No" System.exit(0) System.exit System 0 String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt(),b = sc.nextInt(),c = sc.nextInt(),d = sc.nextInt(),z = 0;
        while(true){
            c -= b;
            a -= d;
            if(c <= 0) {
                System.out.println("Yes");
                System.exit(0);
            }if(a <= 0){
                System.out.println("No");
                System.exit(0);
            }
        }
    }
}
