Counting Sundays
You are given the following information, but you may prefer to do some research for yourself.
 1 Jan 1900 was a Monday.
 Thirty days has September,
April, June and November.
All the rest have thirtyone,
Saving February alone,
Which has twentyeight, rain or shine.
And on leap years, twentynine.  A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
Solution




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