#include <bits/stdc++.h>
using namespace std;
#define ll long long
struct node{
	ll asc;
	ll num;
};
bool cmp(node a,node b){
	if(a.num==b.num){
		return a.num>b.num;
	}
	return a.asc<b.asc;
}
void solu(){
	ll n;
	cin>>n;
	vector<set<string>> team(200);
	vector<node> cnt(200);
	for(int i=0;i<200;i++){
		cnt[i].asc=i;
	}

	
	for(int i=0;i<n;i++){
		
		string name;
		cin>>name;
		
		char problem;
		cin>>problem;
		
		string state;
		cin>>state;
		
		if(state.front()=='a'){
			ll amount = team[problem].size();
			team[problem].insert(name);
			if(amount != team[problem].size()){
				cnt[problem].num++;
			}
		}
	}
	
	sort(cnt.begin(),cnt.end(),cmp);
	
	cout<<(char)cnt[0].asc<<endl;
	
}
int main(){
	ll q;
	cin>>q;
	while(q--){
		solu();
	}
}