第1行：2个用空格隔开的整数n和C.
第2到n+1行：每行两个整数表示一种币值的硬币．第一个整数V(I≤y≤10^8)，表示币值．
第二个整数B(1≤B≤10^6)，表示约翰拥有的这种硬币的个数．
BZPROAs a reward for record milk production, Farmer John has decided to start paying Bessie the cow a small weekly allowance. FJ has a set of coins in N (1 <= N <= 20) different denominations, where each denomination of coin evenly divides the next-larger denomination (e.g., 1 cent coins, 5 cent coins, 10 cent coins, and 50 cent coins). Using the given set of coins, he would like to pay Bessie at least some given amount of money C (1 <= C <= 100,000,000) every week. Please help him compute the maximum number of weeks he can pay Bessie.
3 6
10 1
1 1 00
5 1 20
111
样例说明
约翰想要每周付给贝茜6美分．他有1个10美分的硬币、100个1美分的硬币、120个5美分的硬币．约翰可以第一周付给贝茜一个10美分的硬币，接着的10周每周付给贝茜2个5芙分硬币，接下来的100周每周付给贝茜一个1美分的硬币和1个5美分的硬币．共计111周．