#include #include using namespace std; using namespace atcoder; #define rep(i, n) for(int i=0;i<(n);++i) #define rep1(i, n) for(int i=1;i<=(n);i++) #define ll long long using mint = modint998244353; using P = pair; using lb = long double; using T = tuple; #ifdef LOCAL # include # define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__) #else # define dbg(...) (static_cast(0)) #endif int main() { int t; cin >> t; while(t--) { int n; cin >> n; bool ans = false; int cnt = 0; int mc = 1e9; rep(i,n) { string x, y; cin >> x >> y; if(x=="a") { for(char c : y) if(c=='a') ans=true; if(!ans) cnt = max(cnt, (int)y.size()); } bool ex = true; for(char c : x) if(c=='a') ex = false; if(ex) { for(char c : y) if(c=='a') mc = min(mc, (int)x.size()); } } dbg(cnt,mc); if(ans || cnt>=mc) { cout << "Yes" << endl; } else{ cout << "No" << endl; } } return 0; }