import java.util.*;

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 t_hit = a;
        int a_hit = c;

        while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.*; util.* java 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 t_hit = a;
        int a_hit = c;

        while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} 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 t_hit = a;
        int a_hit = c;

        while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int c = sc.nextInt();
        int d = sc.nextInt();
        int t_hit = a;
        int a_hit = c;

        while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        }
    } 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 t_hit = a; t_hit a int a_hit = c; a_hit c while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        } true {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        } a_hit = a_hit - b a_hit a_hit - b a_hit b t_hit = t_hit - d t_hit t_hit - d t_hit d if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            } a_hit <= 0 a_hit 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; if (t_hit <= 0) {
                System.out.println("No");
                break;
            } t_hit <= 0 t_hit 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args
import java.util.*;

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 t_hit = a;
        int a_hit = c;

        while (true) {
            a_hit = a_hit - b;
            t_hit = t_hit - d; //後
            if (a_hit <= 0) {
                System.out.println("Yes");
                break;
            }else if (t_hit <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
}