import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        char flg = 0x03FF;

        for (int i = 0; i < n; i++) {
            int a = sc.nextInt();
            int b = sc.nextInt();
            int c = sc.nextInt();
            int d = sc.nextInt();

            if ("NO".equals((sc.next()))) {
                flg &= 0 << a;
                flg &= 0 << b;
                flg &= 0 << c;
                flg &= 0 << d;
            }
        }
        for (int i = 0; i < 11; i++) {
            if ((flg & 1 << i) != 0) {
                System.out.println(i);
                break;
            }
        }
    }
}