# 1-OR-3-SAT is in P

1-OR-3-SAT:

Input: 3-CNF formula $$\varphi$$

Question: whether there is an assignment $$x$$ such that in each clause there are one or three true literals.

I need to show that this problem is in $$P$$. I tried to construct a reduction from this problem to 2-SAT that is in $$P$$. What can I try here?