51 Days
Three blondes walk into a bar and order a round of drinks. One of the blondes and makes a toast to "51 days." After a while they order another round, and they toast agian "only 51 days."

Now the bartender is curious and asks what does "51 days" mean?

One of the blondes tell him "we just finished a jigsaw puzzle and it only took 51 days. It says 4-7 years on the box."