How To Merge Columns With Same Data In Excel

I've found macro, which merge rows with the same data

Example:

BEFORE:

january
1st

january
2nd

[Code] ........

Macro:

Option Explicit
Sub MergeSame()
Dim r As Range, c As Range
Dim i As Long, j As Long
Set r = Range("a1", Cells(Rows.Count, "a").End(xlUp))

[Code] .....

But i need use the same procedure for columns, it means:

BEFORE

A
B
C
D
E
F

january
january
january
february
february
february

AFTER

A
B
C
D
E
F

january
february

I've tried modified macro marked above, but without success...