#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <climits>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <stack>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <sstream>
#include <functional>
#include <ctime>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n)  FOR(i,0,n)
#define CLEAR(d) memset((d), 0, (sizeof((d))))
#define ALL(c) (c).begin(), (c).end()
#define ABS(x) ((x < 0) ? -(x) : (x))
#define SORT(x) sort((x).begin(), (x).end())
#define RSORT(x) sort((x).begin(), (x).end(), greater<int>() )
#define SIZE(a) ((int)((a).size()))
#define MAX3(a, b, c) (max(max((a), (b)), (c)))
#define MIN3(a, b, c) (min(min((a), (b)), (c)))
#define MOD 1000000007
#define EPS 1e-5
#define PI  (acos(-1))
#define INF 10000000
//===================================================

int main()
{
    int n, a[4];
    string s;
    int f[10]; // 0 可能性なし 1 可能性あり
    REP(i, 10) f[i] = 1;
    cin >> n;
    REP(i, n) {
        REP(j, 4) cin >> a[j];
        cin >> s;
        if (s == "NO") {
            REP(j, 4) f[a[j]] = 0;
        }
        else {
            REP(j, 10) {
                bool fla = true;
                REP(k, 4) {
                    if (a[k] == j && f[j] != 0) {
                        fla = false;
                    }
                }
                if (fla) f[j] = 0;
            }
        }
    }
    REP(i, 10) {
        if (f[i]) {
            printf("%d\n", i);
            break;
        }
    }
    return 0;
}