codechef code

/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Codechef2
{
    static int rep(char a,String s)
    {
        int p=0;
        for(int i=0;i<s.length();++i)
        {
            if(a==s.charAt(i))
            {
                p=1;
                //System.out.println("Fuck you "+a+" "+s.charAt(i));
            }
        }
        return p;
    }
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner sc=new Scanner(System.in);
        int T=sc.nextInt();
        for(int i=0;i<T;++i)
        {
            int N=sc.nextInt();
            sc.nextLine();
            String s[]=new String[N];
            for(int j=0;j<N;++j)
            s[j]=sc.nextLine();
            int d=0;
            int d1=0;
            for(int j=0;j<s[0].length();++j)
            {
                int p=0;
                d=0;
                char c=s[0].charAt(j);
                for(int k=0;k<j;++k)
                {
                    if(s[0].charAt(k)==c)
                    p=1;
                }
                if(p!=1)
                {
                    
                    for(int k=1;k<N;++k)
                    {
                        int c1=rep(c,s[k]);
                        if(c1==1)
                        ++d;
                    
                        /*int co=0;
                        * String s2=s[k];
                            * for(int l=0;l<s2.length();++l)
                            * {
                            *     if(c==s2.charAt(l)) 
                            *     {
                            *         ++co;
                            *         System.out.println(co);
                            *         break;
                            *       }
                            *   }*/
                    
                            //if(c1==(N-1))
                            //++d;
                    }
                    if(d==(N-1))
                    ++d1;
                }
            }
            System.out.println(d1);
        }
    }
}