Time limit
2s
Memory limit
128 MB
There is a set of N distinct positive integers. If all of these integers are concatenated in some order, they form one large integer. For example, concatenating {5221, 40, 1, 58, 9} in that order gives 5221401589.
Park Seongwon chooses one permutation of the integers uniformly at random and treats it as the answer. A permutation is correct if the concatenated integer is divisible by K.
Find the probability that Park Seongwon accidentally chooses a correct permutation, written as a reduced fraction.
The first line contains the number N of integers in the set. N is a positive integer no greater than 15.
Each of the next N lines contains one integer from the set. Each integer is positive and has length at most 50.
The last line contains a positive integer K. K is no greater than 100.
Print the answer as a reduced fraction in the form p/q, where p is the numerator and q is the denominator. If the probability is 0, print 0/1. If the probability is 1, print 1/1.