instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
sCMyALRSDknURKqZDlqFf, oEIfHyALRSDknUrnMebev
answer:
yALRSDknU


question:
VRXUhOYfTul, JqZUhOYKq
answer:
UhOY


question:
GvHQAMEiChXLHfaiTiRN, ZIqftZLehQAMEiChXLHteJTK
answer:

QAMEiChXLH