[HelloNurse]

Since a proof is a proof, the methods are a matter of taste. Driving away from pontless reductio ad absurdum arguments is a good thing, but sometimes putting in the spotlight the object that need to be matched or counted instead of bare numbers can be useful. For instance, in the ranch example I'd ensure that I'm counting correctly by considering the cowboys and horses in the connected components of the bipartite graph whose edges represent exclusive horse ownership: each connected component contains 0 or 1 cowboys and 1 or more horses.