import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int tHp = sc.nextInt(); tHp sc.nextInt() sc.nextInt sc int tAtk = sc.nextInt(); tAtk sc.nextInt() sc.nextInt sc int aHP = sc.nextInt(); aHP sc.nextInt() sc.nextInt sc int aAtk = sc.nextInt(); aAtk sc.nextInt() sc.nextInt sc boolean Tattack = true; Tattack true while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        } tHp > 0 && aHP > 0 tHp > 0 tHp 0 aHP > 0 aHP 0 {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        } if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            } Tattack {
                aHP -= tAtk;
                Tattack = false;
            } aHP -= tAtk aHP tAtk Tattack = false Tattack false {
                tHp -= aAtk;
                Tattack = true;
            } tHp -= aAtk tHp aAtk Tattack = true Tattack true if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } tHp > 0 tHp 0 {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int tHp = sc.nextInt();
        int tAtk = sc.nextInt();
        int aHP = sc.nextInt();
        int aAtk = sc.nextInt();
        boolean Tattack = true;

        while (tHp > 0 && aHP > 0) {
            if (Tattack) {
                aHP -= tAtk;
                Tattack = false;
            } else {
                tHp -= aAtk;
                Tattack = true;
            }
        }
        if (tHp > 0) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}