#define _CRT_SECURE_NO_WARNINGS
#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0) 
#include<unordered_map>
#include<unordered_set>
#include<bits/stdc++.h>
#include<array>
using namespace std;
typedef long long ll;
typedef pair<ll, ll>pi;
#define int ll
#define X first
#define Y second
#define fer(i,a,n) for(ll i=a;i<=n;i++)
#define ref(i,n,a) for(ll i=n;i>=a;i--)
#define endl '\n'
#define mem(a,x) memset(a,x,sizeof a)
#define ac IO;int t;cin>>t;while(t--)solve()
#define AC signed main(){IO;solve();}
#define NO {cout<<"No"<<endl;return;}
#define YES {cout<<"yes"<<endl;return;}
#define re(a) {cout<<a<<endl;return;}
#define all(v) v.begin(),v.end()
//ofstream fout("out.txt", ios::out);
//ifstream fin("in.txt", ios::in);
//#define cout fout
//#define cin fin
//--------------------瑞神神中神--------------------

const int N = 1e5 + 10;
set<string>se;
string s[N];

bool cmp(string a, string b)
{
	if (a.size() ^ b.size())return a.size() < b.size();
	return a < b;
}

void solve()
{
	int n;
	cin >> n;
	fer(i, 1, n)
	{
		cin >> s[i];
	}
	sort(s + 1, s + n + 1, cmp);
	int ans = 0;
	fer(i, 1, n)
	{
		bool flag = 1;
		int len = s[i].size();
		if (len == 1)
		{
			se.insert(s[i]);
			ans = len;
			continue;
		}
		string res = s[i].substr(1, len - 1);
		if (se.find(res) == se.end())flag = 0;
		res = s[i].substr(0, len - 1);
		if (se.find(res) == se.end())flag = 0;
		if (flag)
		{
			se.insert(s[i]);
			ans = len;
		}
	}
	cout << ans << endl;
}

AC