#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
const int MOD = 1000000007;
const int INF = 1e14;
using Graph = vector<vector<int>>;

signed main(){
  vector<bool> fg(10, 1);
  int N;
  cin >> N;
  for( int i = 0; i < N; i++ ){
    int A, B, C, D;
    cin >> A >> B >> C >> D;
    string S;
    cin >> S;
    if( S == "NO" ){
      fg[A] = 0;
      fg[B] = 0;
      fg[C] = 0;
      fg[D] = 0;
    }else{
      for( int j = 0; j < 10; j++ ){
        if( j != A && j != B && j != C && j != D ) fg[j] = 0;
      }
    }
  }

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