#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline void solve() {
  int n;
  cin >> n;
  vector<pair<string, string>> v(n);
  rep(i, n) cin >> v[i].first >> v[i].second;
  bool exi = false;
  rep(i, n) if (v[i].first == "a") exi = true;
  if (!exi) {
    cout << "No" << '\n';
    return;
  }
  rep(i, n) {
    if (v[i].first == "a" && v[i].second.contains("a")) {
      cout << "Yes" << '\n';
      return;
    }
  }
  int maxim = 0, minim = 1e9;
  rep(i, n) {
    if (v[i].first == "a") {
      maxim = max(maxim, (int) v[i].second.size());
    }
    if (!v[i].first.contains("a")) {
      minim = min(minim, (int) v[i].first.size());
    }
  }
  cout << (maxim >= minim ? "Yes" : "No") << '\n';
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}