A.Lotus and Characters(技巧 + 思維)

Problem Description

Lotus has n kinds of characters,each kind of characters has a value and a amount.She wants to construct a string using some of these characters.Define the value of a string is:its first character‘s value*1+its second character‘s value *2+...She wants to calculate the maximum value of string she can construct.Since it‘s valid to construct an empty string,the answer is always ≥0。

Input

First line is T(0≤T≤1000) denoting the number of test cases.For each test case,first line is an integer n(1≤n≤26),followed by n lines each containing 2 integers vali,cnti(|vali|,cnti≤100),denoting the value and the amount of the ith character.

Output

For each test case.output one line containing a single integer,denoting the answer.

Sample Input

2
2
5 1
6 2
3
-5 3
2 1
1 1

Sample Output

35
5

BestCoder Round #91