The bartender offers him a warm smile and says, "For you, no charge".
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Because all the fans left!
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The question is irrelevant, since you couldn't find the dolls even if you knew how many. (Note: Well, this was a good joke in 1983-84. . . .)
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Seven. One to install the new bulb and six to figure out what to do with the old one for the next 10,000 years.
or