Count Fridays the 13th

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Some superstitious people believe that Friday the 13th13th is a day that is very unlucky. However, Sergey does not agree with them. In order to prove this to people that nothing scary will happen, he wants to choose two dates and count the number of Friday the 13th13th's between them (both inclusive). If this number is reasonably large, he will be able to tell that it is just a regular day. But

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solution.cppC++17

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