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

struct node{
	string a;
	char ti;
	string result;
};

bool cmp(node x, node y){
	if(x.a.size() == y.a.size()){
		return x.a[x.a.size()-1] > y.a[y.a.size()-1];
	} else return x.a.size() > y.a.size();
}

int main(){
	int t;
	cin >> t;
	
	while(t--){
		node c[1000000];
		int n, i;
		int *SUM = new int[26]();
		int *sum = new int[26]();
		cin >> n;
		for(i = 0; i < n; i++){
			string str, strr;
			char qq;
			int p = 1;
			cin >> str >> qq >> strr;
			if(strr == "rejected") continue;
			else {
				c[i].a = str;
				c[i].ti = qq;
				c[i].result = strr;
			}
		}
		sort(c, c+n, cmp);
		for(i = 0; i < sizeof(c); i++){
			if(i == 0){
//				if(c[i].result == "rejected")continue;
					for(int j = 0; j < 26; j++){
						sum[j] = 0;
					}
				if(sum[c[i].ti - 'A'] == 0){
					SUM[c[i].ti - 'A']++;
					sum[c[i].ti - 'A'] = 1;
				}
			}else {
				if(c[i].a == c[i-1].a){
//					if(c[i].result == "rejected")continue;
					if(sum[c[i].ti - 'A'] == 0){
						SUM[c[i].ti - 'A']++;
						sum[c[i].ti - 'A'] = 1;
					} else continue;
				}
				if(c[i].a != c[i-1].a){
					for(int j = 0; j < 26; j++){
						sum[j] = 0;
					}
//					if(c[i].result == "rejected")continue;
					if(sum[c[i].ti - 'A'] == 0){
						SUM[c[i].ti - 'A']++;
						sum[c[i].ti - 'A'] = 1;
					}
				}
			}
		}
		int k = 0, l = 0;
		for(i = 0; i < 26; i++){
			if(SUM[i] > k) {k = SUM[i]; l = i;}
//			cout << SUM[i] << endl;
		}
		
		char s = l + 'A';
		cout << s;
		if(t != 0) cout << endl;
	}
	
	return 0;
}