 Pair Sum in Vector
##### Submissions: 3684   Accuracy: 82.49%   Difficulty: Easy   Marks: 2
Associated Course(s):   Fork CPP

Pairs and vectors can be used together to achieve some amazing results. Here we will learn to use a vector that holds pairs.
You are given a vector V of size n. The vector hold pair of integers. Example V={(1,2),(3,4)...}. Now, you need to sum the second elements.

Input Format:
The first line of input contains T denoting the number of testcases. T testcases follow. Each testcase contains two lines of input. The first line contains n denoting the size of the array. The second line contains 2*n elements.

Output Format:
For each testcase, in a new line, print the required output.

Since this is a function problem, you don't need to take any input. Just complete the provided function sum().

Constraints:
1 <= T <= 100
1 <= n <= 107
0 <= Vi <= 107

Examples:
Input:

1
5
1 2 3 4 5 6 7 8 9 10
Output:
30

Explanation:
Testcase1:

v= 1,2
v= 3,4
v= 5,6
v= 7,8
v= 9,10
Now we sum all the second elements of a pair. So 2+4+6+8+10=30

#### ** For More Input/Output Examples Use 'Expected Output' option **

Author: Soul_xhacker

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