import 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();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    }

} import java.util.*; util.* java 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();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("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();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    } main {
        Scanner sc = new Scanner(System.in);
        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("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 sc.close() sc.close sc boolean isWin = false; isWin false boolean isTakahashiTurn = true; isTakahashiTurn true while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        } true {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        } if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            } isTakahashiTurn {
                C -= B;
                isTakahashiTurn = false;
            } C -= B C B isTakahashiTurn = false isTakahashiTurn false {
                A -= D;
                isTakahashiTurn = true;
            } A -= D A D isTakahashiTurn = true isTakahashiTurn true if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            } A <= 0 A 0 {
                break;
            } break; if (C <= 0) {
                isWin = true;
                break;
            } C <= 0 C 0 {
                isWin = true;
                break;
            } isWin = true isWin true break; if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } isWin {
            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 A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            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 A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    }

} Main
import 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();
        sc.close();

        boolean isWin = false;
        boolean isTakahashiTurn = true;
        while (true) {
            if (isTakahashiTurn) {
                C -= B;
                isTakahashiTurn = false;
            } else {
                A -= D;
                isTakahashiTurn = true;
            }
            if (A <= 0) {
                break;
            } else if (C <= 0) {
                isWin = true;
                break;
            }
        }
        if (isWin) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    }

}
