This is not an objective way. You will fire most valuable people (those who knows how stuff works) and you will keep junior grunts who type code by what seniors tells them.

Correct approach would be understand why there are so many people, figure out what is their job and then start removing those who are deemed unnecessary.

i.e. Imagine that you would come to new codebase and start throwing out code which does not appears to do anything and then be surprised that it is not possible to compile or you can't deploy or whole application will start crashing at random intervals.