Extracting numbers from a String?

Hi All

I have a list of about 1000 people, and each person corresponds to a cell. At the beginning of each cell, this a number which corresponds to that person, and I need to be able to show those numbers in another cell. I did use =left, which did work, but my problem is that not every number has the same number of digits. I realise this is probably simple, but could you please point me in the right direction? Refer to picture for context.
Screen Shot 2014-02-12 at 8.09.37 pm.jpg

Thanks for your help