Buying Hay Farmer Melissa is running out of supplies and needs to purchase H (1 <= H <= 50,000) pounds of hay for her cows. She knows N (1 <= N <= 100) hay suppliers conveniently numbered 1..N. Supplier i sells packages that contain P_i (1 <= P_i <= 5,000) pounds of hay at a cost of C_i (1 <= C_i <= 5,000) dollars. Each supplier has an unlimited number of packages available, and the packages must be bought whole. Help FM by finding the minimum cost necessary to purchase at least H pounds of hay. PROBLEM NAME: buyhay INPUT FORMAT: * Line 1: Two space-separated integers: N and H * Lines 2..N+1: Line i+1 contains two space-separated integers: P_i and C_i SAMPLE INPUT: 2 15 3 2 5 3 OUTPUT FORMAT: * Line 1: A single integer representing the minimum cost FM needs to pay to obtain at least H pounds of hay. SAMPLE OUTPUT: 9 OUTPUT DETAILS: FM can buy three packages from the second supplier for a total cost of 9.