#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cmath>
#include <iomanip>
#include <map>
using namespace std;
typedef long long LL;

int main(){
    int N;
    cin >> N;
    vector<vector<int> > num(N);
    vector<int> judge(N);
    for(int i = 0; i < N; i++){
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        num[i].push_back(a);
        num[i].push_back(b);
        num[i].push_back(c);
        num[i].push_back(d);
        string j;
        cin >> j;
        if(j == "YES"){
            judge[i] = 1;
        }else{
            judge[i] = 0;
        }
    }
    int ans = -1;
    for(int i = 0; i <= 9; i++){
        bool flag = true;
        for(int j = 0; j < N; j++){
            if(judge[j]){
                if(num[j][0] != i && num[j][1] != i && num[j][2] != i && num[j][3] != i){
                    flag = false;
                }
            }else{
                if(num[j][0] == i || num[j][1] == i || num[j][2] == i || num[j][3] == i){
                    flag = false;
                }
            }
        }
        if(flag){
            ans = i;
        }
    }
    cout << ans << endl;
    return 0;
}