Longest Substring


Two strings are given, find the length of longest common substring.

Write a function solve that have the following parameter(s):
1.) first string
2.) second string

Example
Input:
s1 = DASH
s2 = DAB
Output:
2

Explanation
'DA' is the longest common substring.

Constraints
• The length of string will be greater than or equal to 1 and less than or equal to 1000