Deals on Cookies
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It is lunch time again and I am starving. I would like to buy some cookies from a small Cafe, named Cafe CS201, owned and operated by CSC201. Cafe CS201 offen offers discounts for buying multiple cookies. I wonder which of the discounts provides the best values. For this problem, please write a program to help me find the best deal.

Input
The input contains multiple scenarios. Each scenario starts with a line containing two numbers N ( 1<= N <=10) and M( 1<= M <=20), N means there are N deals available, M means the max amount of cookies I want to buy (I may buy less if I get the best deal). Following N lines, each line has two numbers: x and y which represent an offer to buy x cookies for $y. The input will terminated by a line containing the characters 0 0.

Output
For each scenarios, print Purchase x cookies for $y for the best offer that matches requirements (the best deal but less or equal to the number of cookies I want to buy). If there are multiple best offers, print the one which buys more tickets (but still be less or equals to the number of cookies I want to buy). If there is no suitable offer (may require to buy more cookies than I want to), print No good deals.

Sample input data                        Sample Output
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5 6                                      Purchase 6 cookies for $6 
12 10                                    Purchase 3 cookies for $5
9 8                                      Purchase 1 cookies for $3 
6 6                                      Purchase 2 cookies for $4
3 3                                      No good deals 
1 2
3 5
1 3
3 5
4 7
3 2
3 5
1 3
4 7
3 2
3 6
1 2
2 4
1 3
4 10
0 0

Mình cần giúp về assignment của Java. Bài lần này professor của mình không có nói gì về method để viết chương trình. Nên mình đang không biết phải bắt đầu từ đâu. Mong mọi người cho xin vài ý kiến.