In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Ex Input:
bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc

Ex Output:
HPpvVtFQN


Ex Input:
ohueEOjHvAuoFVmMFft, ovdJPqOjHvAuoFVGbvxzlnE

Ex Output:
OjHvAuoFV


Ex Input:
XJnMxn, oNnMpW

Ex Output:

nM