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

Q: STvKOHq, XMGvKOdyM

A: vKO
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Q: nYoRQU, gQoRZQ

A: oR
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Q: UmYbssMbmsXkKQuzNasLOib, EMqlbmsXkKQuzNcyHrpZXOQW

A:
bmsXkKQuzN
****