Given a set of strings, find the longest common substring.
"Easy","Expert","Elephant"
The longest common substring among the given strings "Easy," "Expert," and "Elephant" is "E".
Complete the following task based on the instruction and optional input provided.### Instruction:
Given a set of strings, find the longest common substring.

### Input:
"Easy","Expert","Elephant"

### Output:
The longest common substring among the given strings "Easy," "Expert," and "Elephant" is "E".