CF2148A Sublime Sequence

Farmer John has an integer $ x $ . He creates a sequence of length $ n $ by alternating integers $ x $ and $ -x $ , starting with $ x $ . For example, if $ n = 5 $ , the sequence looks like: $ x, -x, x, -x, x $ . He asks you to find the sum of all integers in the sequence.

The first line contains an integer $ t $ ( $ 1 \leq t \leq 100 $ ) — the number of test cases. The only line of input for each test case is two integers $ x $ and $ n $ ( $ 1 \leq x, n \leq 10 $ ).

For each test case, output the sum of all integers in the sequence.