#include <iostream>
#include <stdio.h>
#include <map>
#include <vector>
using namespace std;
int cnt;
map<int, int> idx;
int fanIdx[233];
int test[233][2];
int res[233][2];
int getID(int yid){
	map<int, int>::iterator it = idx.find(yid);
	if(it != idx.end()){
		return it->second;
	}
	idx.insert(pair<int, int>(yid, cnt));
	fanIdx[cnt] = yid;
	cnt++;
	return cnt-1;
}

int main() {
	int t;
	scanf("%d", &t);
	for(int ii = 0; ii < t; ii++){
		int n;
		scanf("%d", &n);
		idx.clear();
		cnt = 0;
		vector<int> posN;
		int used[233] = {0};
		for(int i = 0; i < n; i++){
			int a,b,c;
			char f1,f2;
			scanf("%d\n%d\n%c\n%d\n%c", &a, &b, &f1, &c, &f2);
			int ida = getID(a), idb = getID(b), idc = getID(c);
			test[ida][0] = idb, test[ida][1] = idc;
			res[ida][0] = (f1=='Y'), res[ida][1] = (f2=='Y');
			if(!res[ida][0]){
				if(!used[idb]) posN.push_back(idb);
				used[idb]++;
			}
			if(!res[ida][1]){
				if(!used[idc]) posN.push_back(idc);
				used[idc]++;
			}
		}
		int huai = 0;
		int arg = -1;
		int sz = posN.size();
		for(int i = 0; i < sz; i++){
			int idh = posN[i];
			bool kywh = 1;
			for(int j = 0; j < cnt; j++){
				if(j==idh) continue;
				if((res[j][0] && test[j][0]==idh) || (!res[j][0] && test[j][0]!=idh)){
					kywh=0; break;
				}
				if((res[j][1] && test[j][1]==idh) || (!res[j][1] && test[j][1]!=idh)){
					kywh=0; break;
				}
			}
			if(kywh){
				huai++;
				arg=idh;
				if(huai>=2) break;
			}
		}
		if(huai-1){
			printf("impossible\n");
		}
		else{
			printf("%d\n", fanIdx[arg]);
		}
	}
	return 0;
}