1,000,001: One to change the bulb and 1,000,000 to rebuild civilization to the point where they need light bulbs again.
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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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None: they just deny that the bulb ever went out in the first place.
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