#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     int t;     cin >> t;     while (t--) {       unordered_map<char, int> mp;       int n;       cin >> n;       string arr[n];       for (int i = 0; i < n; i++) {         cin >> arr[i];         for (auto c : arr[i]) {           mp[c]++;         }       }       bool ok = true;       for (auto p : mp) {         if (p.second % n != 0) {           ok = false;           break;         }       }       cout << ((ok) ?  YES n  :  NO n );     }     return 0;   }   