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

Example Input: inquDFuJxtBaaFGCaRzO, NYcnWDuDFuJxtBafxZWCUw
Example Output: uDFuJxtBa

Example Input: OyXwTWbLByC, yODnTWbLWYzc
Example Output: TWbL

Example Input: UfATWzCRiucfw, VGMATWzCRrjKa
Example Output:
ATWzCR