import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int takahashiA = sc.nextInt(); takahashiA sc.nextInt() sc.nextInt sc int takahashiKougeki = sc.nextInt(); takahashiKougeki sc.nextInt() sc.nextInt sc int aokiC = sc.nextInt(); aokiC sc.nextInt() sc.nextInt sc int aokiKougeki = sc.nextInt(); aokiKougeki sc.nextInt() sc.nextInt sc while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        } takahashiA > 0 && aokiC > 0 takahashiA > 0 takahashiA 0 aokiC > 0 aokiC 0 {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        } aokiC -= takahashiKougeki aokiC takahashiKougeki if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            } aokiC <= 0 aokiC 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; takahashiA -= aokiKougeki takahashiA aokiKougeki if (takahashiA <= 0) {
                System.out.println("No");
                break;
            } takahashiA <= 0 takahashiA 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashiA = sc.nextInt();
        int takahashiKougeki = sc.nextInt();
        int aokiC = sc.nextInt();
        int aokiKougeki = sc.nextInt();

        while (takahashiA > 0 && aokiC > 0) {
            aokiC -= takahashiKougeki;
            if (aokiC <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashiA -= aokiKougeki;
            if (takahashiA <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
}