/*状态AC*/
import java.util.Scanner;

public class hdu1238_Substrings {
	static String[] str = new String[105];

	public static void main(String[] args) {
		Scanner sc =new Scanner (System.in);
		int tcase = sc.nextInt();
		while(tcase-->0){
			int  Min=1000,k=0;
			int n =sc.nextInt();
			/*找到最小串*/
			for(int i=0;i<n;i++){
				str[i] = sc.next();
				if(str[i].length()<Min) {
					Min = str[i].length();
					k = i;
				}
			}
			int Max = 0;
			String str1,str2;//子串以及反子串
			boolean flag = true; //是否出现过
			for(int i=0;i<str[k].length();i++){//枚举子串的头
				for(int j=i;j<str[k].length();j++){//子串的尾
					str1 = str[k].substring(i,j+1);
					str2 = reverse(str1);
					//System.out.println(str1+str2);
					int len = str1.length();
					/*枚举所有串*/
					for(int t=0;t<n;t++){
						 
						if(str[t].indexOf(str1)==-1&&str[t].indexOf(str2)==-1) {//当正反子串在母串中都未发现时即跳出
							flag = false;
							break;
						}
					}
					if(flag&&len>Max) Max = len; 
					flag = true;
				}
			}
			System.out.println(Max);
		}
	}
    

	public static String reverse(String s) {
		char ch[] = s.toCharArray();
		int start = 0, end = ch.length - 1;
		char temp;
		while (start < end) {
			temp = ch[start];
			ch[start] = ch[end];
			ch[end] = temp;
			start++;
			end--;
		}
		String s1 = String.copyValueOf(ch);
		return s1;
	}
}