#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<sstream>
#include<cstring>
#include<string>
#include<vector>
#include<set>
#include<stack>
#include<queue>
#include<map>
#include<cmath>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
#define ll long long
#define MAX_N 1000005
#define gcd(a,b) __gcd(a,b)
#define mem(a,x) memset(a,x,sizeof(a))
#define mid(a,b) a+b/2
#define stol(a) atoi(a.c_str())//string to long
string temp[10];
string c = "ACGT";
int pos[10];
int len[10];
int deep;
int n;
int ans(){
    int maxn = 0;
    for(int i = 0; i < n; i++){
        maxn = max(maxn,len[i]-pos[i]);
    }
    return maxn;
}
int dfs(int step){
    if(step + ans() > deep)
        return 0;
    if(!ans())//满足构造序列包含所有序列
        return 1;
    int temp1[10];
    for(int i = 0; i < 4; i++){

        int flag = 0;
        for(int j = 0; j < n; j++)
            temp1[j] = pos[j];

        for(int j = 0; j < n; j++){
            if(temp[j][pos[j]] == c[i]){
                flag = 1;
                pos[j]++;
            }
        }
        if(flag){
            if(dfs(step+1))
                return 1;
            for(int j = 0; j < n; j++)
                pos[j] = temp1[j];
        }
    }
    return 0;
}
int main(){
//    freopen("D:\\in.txt","r",stdin);
    int T;
    scanf("%d",&T);
    while(T--){
        scanf("%d",&n);
        deep = 0;
        for(int i = 0; i < n; i++){
            cin>>temp[i];
            len[i] = temp[i].length();
            pos[i] = 0;
            deep = max(deep,len[i]);
        }
        while(1){
            if(dfs(0))
                break;
            ++deep;
        }
        printf("%d\n",deep);
    }
    return 0;
}