
Module Module1
    Structure HUMAN
        Public hp As Long
        Public power As Long
        Public downCount As Long
    End Structure

    Sub main()
        Dim user2 As List(Of String) = New List(Of String)(Split(Console.ReadLine(), " "))
        Dim result As String = "No"
        Dim enemy As HUMAN
        Dim user As HUMAN

        enemy.hp = user2(0)
        enemy.power = user2(1)
        user.hp = user2(2)
        user.power = user2(3)
        enemy.downCount = Math.Ceiling(enemy.hp / user.power)
        user.downCount = Math.Ceiling(user.hp / enemy.power)

        If enemy.downCount >= user.downCount Then result = "Yes"

        Console.WriteLine(result)
    End Sub
End Module