instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
tyVlHfTPLRSdFilXnSfqQ, bkTPLRSdFiMgXC
answer:
TPLRSdFi


question:
bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc
answer:
HPpvVtFQN


question:
ZnUHsIxgVgJEDyIC, qTBtsIxgVgGZ
answer:

sIxgVg