Yurii sure can solve task thoughhe array consist n positive integer Lets subarray alr good follow condition simultaneously satisfy l1 leq r1 ie subarray length 3 a_l oplus a_r a_l1a_l2ldotsa_r2a_r1 oplus denote bitwise XOR operation in word subarray good bitwise XOR border element equal sum rest element Yurii wants calculate total number good subarray what equal toan array c subarray array d c obtain d deletion possibly zero element begin possibly zero element end