#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
using ll = long long;
const ll MOD = 998244353;
#include<atcoder/all>
using namespace atcoder;
using mint = modint998244353;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll t;cin>>t;
  while(t--){
    ll n;cin>>n;
    ll mb=0;
    bool f=false;
    vector<vector<ll>> S;
    while(n--){
        string x,y;cin>>x>>y;
        ll cxa=0,cxb=0,cya=0,cyb=0;
        rep(i,x.size()){
            if (x[i]=='a')cxa++;
            else cxb++;
        }
        rep(i,y.size()){
            if(y[i]=='a')cya++;
            else cyb++;
        }
        if(cxa==1 && cxb==0){
            if(cya>0 &&cya+cyb>1){
                f=true;
            }else{
                mb=max(mb,cyb);
            }
        }else if(cxa==0){
            S.push_back({cxb,cya,cyb});
        }
    }
    for(auto I:S){
        if(I[0]>mb)continue;
        if(I[0]<mb &&I[1]>0){
            f=true;
            break;
        }
        if(I[0]<=mb && I[0]<I[1]+I[2]){
            f=true;
            break;
        }
        if (I[0]==mb && I[1]>0 && I[1]+I[2]>1){
            f=true;
            break;
        }
    }
    if(f) cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
  }
}