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

Ex Input:
VTwtMVKmrRvL, WLoVtWtMVKmrDCke

Ex Output:
tMVKmr


Ex Input:
inquDFuJxtBaaFGCaRzO, NYcnWDuDFuJxtBafxZWCUw

Ex Output:
uDFuJxtBa


Ex Input:
ylAUmG, lRAUQj

Ex Output:

AU