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

Ex Input:
mjCEUoPmeKbvCgUtUL, SrHtrPmeKbvYpQAVp

Ex Output:
PmeKbv


Ex Input:
euQWhCovKplukMYznXcD, XAfMhKdzhCovKplukMcMlSuBw

Ex Output:
hCovKplukM


Ex Input:
jxcxFXCTItiRaP, VFYoYcxFXCTCCyAK

Ex Output:

cxFXCT