One

"I mean, what is an un-birthday present?"
"A present given when it isn't your birthday, of course."
Alice considered a little. "I like birthday presents best," she said at last.
"You don't know what you're talking about!" cried Humpty Dumpty. "How many days are there in a year?"
"Three hundred and sixty-five," said Alice.
"And how many birthdays have you?"
"One." - Lewis Carroll