#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

vector<pii> RLE(string S){
    S += 'Z';
    int N = S.size();
    vector<pii> ret;

    int now = S[0] - 'a';
    int cnt = 0;
    rep(i, N){
        if(now == S[i] - 'a'){
            cnt++;
        }
        else{
            ret.push_back({now, cnt});
            cnt = 1;
            now = S[i] - 'a';
        }
    }

    return ret;
}

void solve(int t){
    int N; cin >> N;
    vector<string> X(N), Y(N);
    rep(i, N) cin >> X[i] >> Y[i];

    if(t == 582){
        debug(N);
        debug(X, Y);
    }

    int mx = 0, mn = 1 << 30, vis = 0;
    rep(i, N){
        vector<pii> rx = RLE(X[i]), ry = RLE(Y[i]);
        debug(mx, mn, vis, rx, ry);

        if(X[i] == "a"){
            vis = 1;
            if(ry.size() > 1){
                cout << "Yes" << endl;
                return;
            }
            else{
                if(ry[0].first == 0){ //a
                    cout << "Yes" << endl; 
                    return;
                }
                else {// b;
                    chmax(mx, ry[0].second);
                }
            }
        }
        else if((int)rx.size() > 1){
            continue;
        }
        else{ // b
            if(!rx[0].first) continue;
            chmin(mn, rx[0].second);
        }
    }

    cout << ((mx >= mn) && vis ? "Yes" : "No") << endl;
}


int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    int T = 1;
    cin >> T;
    rep(t, T) solve(t);
}