Let A be an integral series {A
1, A
2, . . . , A
n}.
The zero-order series of A is A itself.
The first-order series of A is {B
1, B
2, . . . , B
n-1},where B
i = A
i+1 - A
i.
The ith-order series of A is the first-order series of its (i - 1)th-order series (2<=i<=n - 1).
Obviously, the (n - 1)th-order series of A is a single integer. Given A, figure out that integer.
The input consists of several test cases. The first line of input gives the number of test cases T (T<=10).
For each test case:
The first line contains a single integer n(1<=n<=3000), which denotes the length of series A.
The second line consists of n integers, describing A
1, A
2, . . . , A
n. (0<=A
i<=10
5)
For each test case, output the required integer in a line.