Problem #8

To convert from the old-style (Julian) calendar to the new (Gregorian) calendar, Pope Gregory decreed that in 1582, Thursday, October 4 (Julian) would be immediately followed by Friday, October 15 (Gregorian). Recall that in the Julian calendar, all years evenly divisible by four are leap years, while in the Gregorian calendar, years evenly divisible by 100 are not leap years unless they are evenly divisible by 400.

For example, 1996 is a leap year in either calendar, 1900 is a leap year in the Julian, but not the Gregorian, and 2000 is a leap year in either.

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