Combine multiple columns into 2 repeating columns (please read explanation) ....

Hello everybody! I hope I can get some help on what I hope is a simple problem. I can't, for the life of me, figure out the resolution.

I have 1 column that I will call my MAIN column, with 3 additional supporting columns of data.

It looks like this -

Main | 1 | (blank) | 3 | 4 |

In another sheet, I would like to reduce this to 2 columns, with the MAIN column repeating as many times as there is data in the other 3 columns, and the second column displaying that data, ignoring blanks.

So it would look like this -

Main | 1 |
Main | 3 |
Main | 4 |

Is there a way to do this via formula or otherwise?

Thanks! Alot!