human
Solve in Python:
Given two strings A and B, find the minimum number of times A has to be repeated such that B is a substring of it. If no such solution, return -1.

For example, with A = "abcd" and B = "cdabcdab". 

Return 3, because by repeating A three times (“abcdabcdabcd”), B is a substring of it.
and B is not a substring of A repeated two times ("abcdabcd").

Note:
The length of A and B will be between 1 and 10000.
assistant
#Here is Python program to find the minimum number of times A has to be repeated such that B is a substring of it.

class Solution:
     def repeatedStringMatch(self, A, B):
 
         times = 1
         tmp = A
         if (not set(B).issubset(set(A))):
             return -1
         maxTime = math.ceil(len(B) / len(A))
         while True:
             if B in A:
                 break
             elif (times <= maxTime):
                 A += tmp
                 times += 1
             else:
                 return -1
         return times