10313 - 丑数
对于一给定的素数集合 S = {p1, p2, ..., pK}, 来考虑那些质因数全部属于S 的数的集合。这个集合包括，p1, p1p2, p1p1, 和 p1p2p3 (还有其它)。这是个对于一个输入的S的丑数集合。 注意：我们不认为1 是一个丑数。 你的工作是对于输入的集合S去寻找集合中的第N个丑数。longint(signed 32-bit)对于程序是足够的。
Input
第 1 行: 二个被空间分开的整数:K 和 N ， 1<= K<=100 ， 1<= N<=100,000.
第 2 行: K 个被空间分开的整数:集合S的元素
Output
单独的一行，写上对于输入的S的第N个丑数。
Examples
Input
4 19 2 3 5 7
Output
27
Hint
Humble Numbers
For a given set of K prime numbers S = {p1, p2, ..., pK}, consider the set of all numbers whose prime factors are a subset of S. This set contains, for example, p1, p1p2, p1p1, and p1p2p3 (among others). This is the set of `humble numbers' for the input set S. Note: The number 1 is explicitly declared not to be a humble number.
Your job is to find the Nth humble number for a given set S. Long integers (signed 32-bit) will be adequate for all solutions.
PROGRAM NAME: humble
INPUT FORMAT
Line 1: Two space separated integers: K and N, 1 <= K <=100 and 1 <= N <= 100,000.
Line 2: K space separated positive integers that comprise the set S.
SAMPLE INPUT (file humble.in) 4 19 2 3 5 7
OUTPUT FORMAT The Nth humble number from set S printed alone on a line. SAMPLE OUTPUT (file humble.out) 27