It is sometimes tricky to figure out the cheapest way to buy things, even in the supermarket where the price of all goods are listed clearly. Just consider what I saw last Saturday about the price of cooking oil: (notice the difference in the sizes of the two price tags) Having a sharp mind (a consequence of regularly taking part in online programming contests), you should have no problem in seeing that the ‘buy-1-get-1-free’ scheme is preferable. But what about your Mum? It is your responsibility as her son/daughter to write her a program that computes the lowest price to buy things in the supermarket, thus helps her to save money. Input The input consists of more than a hundred test cases, each concerning a different item. The first line of each case gives the unit price of buying an item, then a non-negative integer M (≤ 20). This is followed by M lines each containing two numbers N and P (1 < N ≤ 100), which means that you can buy N such items for $P . Finally there is a line containing a list of positive integers K (≤ 100). Output For each of them your program should print the lowest price you need to get K items. Note that you do not have to buy exactly K items; you may consider buying more than K items, and giving the unneeded items to your dear neighbours, if you can save money in this way. Note that all prices P given in the input are floating-point numbers in exactly 2 decimal places, with0<P <1000. Sample Input 22.00 2 2 22.00 4 60.00 24 25.00 2 2 48.00 2 46.00 2 22.00 2 2 22.00

2/2 4 40.00 123 Sample Output Case 1: Buy 2 for $22.00 Buy 4 for $44.00 Case 2: Buy 2 for $46.00 Case 3: Buy 1 for $22.00 Buy 2 for $22.00 Buy 3 for $40.00