#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize(2)
//#pragma GCC optimize(3,"Ofast","inline")
typedef long long ll;
#define pll pair<ll,ll>
const int inf=0x3f3f3f3f;
const int N=1e5+5;
const int mod=99844854;
#define PI 3.1415926
#define fi first
#define se second
ll n,ma;
char ans,s2,s;
string s1,s3;
set<string>se[26];
void solve(){
	cin>>n;ma=0;
	for(int i=1;i<=n;++i){
		cin>>s1>>s2>>s3;
		if(s3[0]=='a'){
			se[s2-'a'].insert(s1);
		}
	}
	for(int i=0;i<26;++i){
		if(se[i].size()>ma)ans='A'+i,ma=se[i].size();
	}
	cout<<ans<<endl;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int __;cin>>__;
    while(__--){
    	solve();
	}
    return 0;
}