#include <iostream>
#include <vector>
#include <cmath>
#include <memory>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <iomanip>
#include <bitset>
#include <string>
#include <list>
#include <deque>
#include <stack>
#include <limits>

#include <atcoder/fenwicktree.hpp>
#include <atcoder/segtree.hpp>
#include <atcoder/modint.hpp>
#include <atcoder/dsu.hpp>

using namespace atcoder;
using namespace std;
using ll = long long;
using ull = unsigned long long;
template <class T>
using max_heap = priority_queue<T>;
template <class T>
using min_heap = priority_queue<T, vector<T>, greater<>>;
ll ll_min = numeric_limits<ll>::min();
ll ll_max = numeric_limits<ll>::max();
ll ALPHABET_N = 26;
using mint = modint998244353;
#define rep(i, n) for (ll i = (ll)0; i < (ll)n; i++)
#define rep_(i, k, n) for (ll i = (ll)k; i < (ll)n; i++)
#define all(a) a.begin(), a.end()

int main()
{
    ll t;
    cin >> t;
    rep(_, t)
    {
        ll n;
        cin >> n;
        bool flag_a = false, flag_b = false;
        string tgt = "";
        vector<string> A(n), B(n);
        rep(i, n) cin >> A[i] >> B[i];
        rep(i, n)
        {
            if (A[i] == "a")
            {
                if (B[i].size() > 1 && find(all(B[i]), 'a') != B[i].end())
                {
                    flag_a = true;
                }
                else if (!flag_a && all_of(all(B[i]), [](char c)
                                           { return c == 'b'; }))
                {
                    flag_b = true;
                    if (tgt.size() < B[i].size())
                    {
                        tgt = B[i];
                    }
                }
            }
        }
        if (flag_a)
        {
            cout << "Yes" << endl;
            continue;
        }
        if (!flag_a && !flag_b)
        {
            cout << "No" << endl;
            continue;
        }
        ll b_len1 = tgt.size() - 1;
        bool ok = false;
        rep(i, n)
        {
            if (all_of(all(A[i]), [](char c)
                       { return c == 'b'; }) &&
                all_of(all(B[i]), [](char c)
                       { return c == 'b'; }) &&
                B[i].size() > A[i].size() && tgt.find(A[i]) != string::npos)
            {
                ok = true;
                break;
            }
            else if (tgt.find(A[i]) != string::npos && B[i].find('a') != string::npos)
            {
                if (b_len1 + (B[i].size() - 1) > 0)
                {
                    ok = true;
                    break;
                }
            }
        }
        cout << (ok ? "Yes" : "No") << endl;
    }
    return 0;
}