#include <iostream>
#include <string>
using namespace std;
int main() {
	bool x[10] = { false };
	int check[6] = { 0 };
	int num[6][4];
	string str[6];
	int N;
	cin >> N;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < 4; j++) {
			cin >> num[i][j];
		}
		cin >> str[i];
	}
	for (int i = 0; i < N; i++) {
		if (str[i] == "NO") {
			for (int j = 0; j < 4;j++) {
				if(x[num[i][j]] != true) x[num[i][j]] = true;
			}
		}
		else {
			for (int j = 0; j < 10;j++) {
				int count = 0;
				for (int k = 0;k < 4; k++) {
					if (num[i][k] == j) {
						count++;
					}
				}
				if (count == 0) {
					x[j] = true;
				}
			}
		}
	}
	for (int i = 0;i < 10;i++) {
		if (x[i] == false) { cout << i << endl; return 0; }
	}
	return 0;
}