A Really Odd Sequence

Following our long-established tradition, the best statements are those kept short.

Given a sequence of integers, find the largest sum of a consecutive subsequence of odd length.

The first line of input contains the number of test cases $z$. The descriptions of the test cases follow.

The first line of each test case contains the length of the sequence $n$ ($1 \leq n \leq 1\,000\,000$).

The next line contains $n$ integers $a\_1, a\_2, \ldots, a\_n$ ($-10^9 \leq a\_i \leq 10^9$), the elements of the sequence.

The total length of all sequences in all test cases does not exceed $5\,000\,000$.

For each test case, output the largest sum on a separate line.