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In the USA, the date is typically written as the month number, followed by the day number, and then the year. In Europe, however, the day comes first, followed by the month and the year. How many days in a year cannot be read unambiguously without knowing which format it is written in

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Obviously, these are the days whose number can be the number of the month, that is, takes a value from 1 to 12. Such days are $12 \cdot 12=144$. But the days, for which the number coincides with the month number, are understood unambiguously. Therefore, the number of days sought is $144-12=132$.