#include <bits/stdc++.h>
using namespace std;

int main()
{
	int n;
	cin >> n;
	vector<bool> check(10, true);
	
	int a, b, c, d;
	string r;
	for(int i = 0; i < n; i++)
	{
		cin >> a >> b >> c >> d >> r;
		if(r == "NO")
		{
			check[a] = false;
			check[b] = false;
			check[c] = false;
			check[d] = false;
		}
		else
		{
			for(int j = 0; j < 10; j++)
			{
				if(j != a && j != b && j != c && j != d) check[j] = false;
			}
		}
	}
	
	for(int i = 0; i < 10; i++)
	{
		if(check[i])
		{
			cout << i << endl;
			return 0;
		}
	}
}