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

UiaECWZf, gRyaECWLGRl
aECW

nOfXJySmVaJIindcJavXh, YpJWmVaJIindcJnoxyRvunG
mVaJIindcJ

sgSVVJPeBtTbanKtoCd, OGjPeBtTbanKjaXc

PeBtTbanK