Hi I just want to know how I can do the following.

I am importing a txt file into excel, on my first column I have numbers

12
30
50
13
99
103
106

So I want to know how can it be done, that when I import this it will put 4 (0000) in front of the two numbers and 3(000) in front of the three numbers by itself

It should look like this

000012
000030

000103
000106