#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
  int N;
  cin >> N;

  vector<int> a(10,1);
  vector<int> x(4);
  string judge;

  for(int i=0; i<N; i++){
    for(int j=0; j<4; j++){
      cin >> x[j];
    }
    cin >> judge;


    if(judge == "NO"){
      for(int j=0; j<4; j++){
        a[x[j]] = 0;
      }
    }
    else{
      for(int j=0; j<10; j++){
        if(count(x.begin(),x.end(),j) == 0) a[j] = 0;
      }
    }
    if(count(a.begin(),a.end(),1) == 1){
      cout << find(a.begin(),a.end(),1) - a.begin() << endl;
      return 0;
    }
  }
}