Fifty-One Days

Three blondes walk into a bar and ask the bartender for three shots
of tequila.
He looks at them and says "OK" and pours their shots.
They all clink glasses and and yell "51 days!"
They then proceed to slam the shots, looking very self-satisfied.
They look back to the bartender and decide to order another round.
This time they pick up the glasses again and, more gleefully yell "only 51 days!"
The bartender finally can't stand wondering what they are talking about and
asks them what they mean by "only 51 days."
One of the blondes looks at him and says very smugly: "Well, we just
finished a jigsaw puzzle and it took us only 51 days!"
"What's so great about that?" the bartender asked.
The blond coolly replied: "Oh really, smartass? The box says 4 to 7 years!!!!"