Shibu and String Game

Shibu is playing a game in which she will be given two strings $A$ and $B$. In order to win the game, she needs to count the number of substrings of $A$ which are also present in $B$. She manages to win the game for smaller strings but it becomes difficult for her as the string size increases. To help her, write a program for her where she can input two strings $A$ and $B$ and get the desired re