#include <bits/stdc++.h>
using namespace std;
int main() {
	int N;
	int X[10];
	for(int i = 0; i < 10; i++) {
		X[i] = 3;
	}
	int A, B, C, D;
	string yesno;
	bool R;
	cin >> N;
	for(int i = 0; i < N; i++) {
		cin >> A >> B >> C >> D;
		cin >> yesno;
		R = yesno == "YES";
		if(R) {
			for(int j = 0; j < 10; j++) {
				if(j != A && j != B && j != C && j != D) {
					X[j] &= 0;
				} else {
					X[j] &= 1;
				}
			}
		} else {
			X[A] = X[B] = X[C] = X[D] = 0;
		}
	}
	int n = -1;
	for(int i = 0; i < 10; i++) {
		if(X[i] && (n < 0 || X[i] == 1)) n = i;
	}
	cout << n << endl;
	return 0;
}