Option Strict On
Module Module1

    Sub Main()
        Dim n As Integer = Convert.ToInt32(Console.ReadLine())
        Dim S As String = Console.ReadLine()
        Dim k As Integer = Convert.ToInt32(Console.ReadLine())
        Dim moji As String = Mid(S, k, 1)
        For i As Integer = 1 To n
            If Mid(S, i, 1) <> moji Then
                Mid(S, i, 1) = "*"
            End If
        Next
        Console.WriteLine(S)
        Console.ReadLine()
    End Sub

End Module