Problem H
Longest Common Substring
                                                                                    
  Given a list of strings, what is the longest substring common to all of them?
Input
The first line of input contains an integer $n$ ($1 \le n \le 1\, 000$), which is the number of strings that follow.
Each of the next $n$ lines contains a single string $s$ ($1 \le |s| \le 100$) consisting only of lower-case letters.
Output
Output a single integer, which is the length of the longest substring common to all of the input strings.
| Sample Input 1 | Sample Output 1 | 
|---|---|
          5 axabcrwmvd abcn tabchwqsl bvrkabcayna tyabc  | 
        
          3  | 
      
