#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
static const double pi = 3.141592653589793;
const ll INF = 1LL << 60;
const ll mod = 1000000007;
const ll imod = 998244353;
using mint = modint998244353;
vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
ll P(ll x, ll n) {
  ll ret = 1;
    while (n > 0) {
      if (n & 1) ret *= x;
      x *= x;
      n >>= 1;
  }
  return ret;
}

void seek(bool f){
  cout << (f ? "Yes" : "No") << endl;
}

int main(){
	int T;
	cin >> T;
	while(T--){
		int N;
		cin >> N;
		vector<string> A(N), B(N);
		rep(i, N){
			cin >> A[i] >> B[i];
		}
		vector<pair<int, int>> PA(N), PB(N);
		rep(i, N){
			int Aa = count(A[i].begin(), A[i].end(), 'a');
			int Ab = count(A[i].begin(), A[i].end(), 'b');
			PA[i] = {Aa, Ab};
			int Ba = count(B[i].begin(), B[i].end(), 'a');
			int Bb = count(B[i].begin(), B[i].end(), 'b');
			PB[i] = {Ba, Bb};
		}
		bool f = false;
		rep(i, N){
			if(A[i] == "a"){
				f = true;
			}
		}
		if(!f){
			cout << "No" << endl;
			continue;
		}
		bool f1 = false;
		rep(i, N){
			if(A[i] == "a" and PB[i].first > 0){
				f1 = true;
			}
		}
		if(f1){
			cout << "Yes" << endl;
			continue;
		}
		int amas = 1e9, bmas = 0;
		rep(i, N){
			if(A[i] == "a"){
				if(PB[i].second == B[i].size()){
					bmas = max(bmas, (int)B[i].size());
				}
			}
			if(PA[i].second == A[i].size()){
				amas = min(amas, (int)A[i].size());
			}
		}
		if(amas <= bmas){
			cout << "Yes" << endl;
		}
		else{
			cout << "No" << endl;
		}
	}
}