题目描述

小青遇到了这样一个问题：Before ACM can do anything, a budget must be prepared and the necessary financial support obtained.

输入格式

The input consists of T test cases. Each test case begins with two integers E and F. On the second line, there is an integer N. Following this are N lines, each specifying a coin type with two integers P and W.

输出格式

Print exactly one line of output for each test case. The line must contain The minimum amount of money in the piggy-bank is X. where X is the minimum amount of money. If the weight cannot be reached exactly, print This is impossible.

样例

样例 1

输入 # 1

2
1 4
3
5 4
5 5
4 4

输出 # 1

The minimum amount of money in the piggy-bank is 6.