#include <algorithm>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <cmath>
#include <stack>
using namespace std;

int main() {
	int N;
	cin >> N;
	bool noTarget[10]={0};

	for (int i = 0;i<N;i++){
		int Na[4];
		string str;
		cin >> Na[0] >> Na[1]>> Na[2]>> Na[3]>> str;

		if (str == "NO"){
			for(int j=0;j<4;j++){
				noTarget[Na[j]] = true;
			}
		}else{
			for (int i = 0;i<10;i++){
				if(i != Na[0] && i != Na[1] && i != Na[2] && i !=Na[3]){
					noTarget[i] = true;
				}
			}
		}
	}

	for (int i = 0;i<10;i++){
		if (!noTarget[i]){
			cout << i << endl;
			return 0;
		}
	}
}