# Special Parity

Level pending

Denote $$U(s)$$ as a function of the maximum number of unit squares that can be formed in a grid with semiperimeter $$s$$ where $$s\in \mathbb Z^+\setminus\{1\}$$ [for example, $$U(6)=9$$].

If $$s_1+s_2$$ and $$|s_1-s_2|$$ are both odd multiples of 2, then what is the parity of $$|U(s_1)-U(s_2)|$$?

Clarification:

• Unit square is a square with side 1.

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