1010 : A+B for Input-Output Practice (X)

Your task is to Calculate a + b.

Input contains multiple test cases. Each test case contains a integer N, and then 2N integers followed in the same line. A test case starting with 0 terminates the input and this test case is not to be processed.

For each line of input, you should calculate and print the sum of a[1]+a[2], a[3]+a[4],...,a[2n-1]+a[2n] in one line. Every two integers separated by a space. 

1 1 2
2 1 2 3 4
3 1 2 3 4 5 6
0

3
3 7
3 7 11

基础