I dunno exactly, but my brother's girlfriend's father's boss's secretary's sister's next-door neighbors' priest's cousin's union shop steward's uncle's Knights Of Columbus club Sergeant-of-Arms's nephew's best friend did it real cheap for me once.
Four. One to change it, one to sing about how heartbroken he is at the loss of the old one, one to sing about how madly in love he is with the new one, and one to go "Yee-Hah!" and throw his cowboy hat in the air.