Function Tokenize(text As String, tokens() As String) As Integer
    Dim As Integer count = 0, posic = 1, start

    While posic <= Len(text)
        If Mid(text, posic, 1) <> " " Then
            start = posic
            While posic <= Len(text) Andalso Mid(text, posic, 1) <> " "
                posic += 1
            Wend
            count += 1
            tokens(count) = Mid(text, start, posic - start)
        End If
        posic += 1
    Wend
    Return count
End Function

Function Buscar(s As String) As Integer
    Dim As Integer n, d, i, j
    Dim As Boolean s_flag
    Dim As String a, b
    Dim As String r(1 To 100) ' Assuming a maximum of 100 tokens

    n = Tokenize(s, r())
    d = 1

    Do
        s_flag = True
        For i = 1 To n
            For j = i + 1 To n
                a = Left(r(i), d)
                b = Left(r(j), d)
                If a = "" Or b = "" Then
                    s_flag = True
                    Exit For
                Elseif a = b Then
                    s_flag = False
                    d += 1
                    Exit For
                End If
            Next j
            If Not s_flag Then Exit For
        Next i
    Loop Until s_flag
    Return d
End Function

Dim As Integer fileNum = Freefile()
If Open("days_of_week.txt" For Input As #fileNum) = 0 Then
    Dim As String s
    While Not Eof(fileNum)
        Line Input #fileNum, s
        Print Buscar(s); " "; s
    Wend
    Close #fileNum
Else
    Print "Error opening file."
End If

Sleep