#include <bits/stdc++.h>
using namespace std;

const int inf = 1e9;

bool has_a(string x) {
	for (char c : x) if (c == 'a') return true;
	return false;
}

void solve() {
	int N; cin >> N;
	string X[N], Y[N];
	for (int i = 0; i < N; i++) cin >> X[i] >> Y[i];
	
	int max_len = 0;
	
	for (int i = 0; i < N; i++) {
		if (X[i] == "a") {
			if (has_a(Y[i])) {
				cout << "Yes" << endl;
				return;
			}
			else {
				max_len = max(max_len, (int)Y[i].size());
			}
		}
	}
	if (max_len == 0) {
		cout << "No" << endl;
		return;
	}
	
	int target = inf;
	for (int i = 0; i < N; i++) {
		if (has_a(X[i]) == false and has_a(Y[i]) == true) {
			target = min(target, (int)X[i].size());
		}
	}
	
	bool exist = false;
	for (int i = 0; i < N; i++) {
		if ((int)X[i].size() <= max_len and has_a(X[i]) == false and has_a(Y[i]) == false) {
			exist = true;
		}
	}
	
	bool ans = ((max_len >= target) or exist);
	
	cout << (ans? "Yes" : "No") << endl;
}

int main() {
    int T; cin >> T;
    while(T--) solve();
}