Option Strict On

Module Module1
    Const n As Int32 = 3
    Dim i As Int32
    Dim c(n - 1), ans As String

    Sub Main()
        For i = 0 To n - 1
            c(i) = Console.ReadLine()
        Next

        For i = 0 To n - 1
            ans &= c(i)(i)
        Next

        Console.WriteLine(ans)
    End Sub

End Module