package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"strconv"
)

func main() {
	sc := NewScanner(os.Stdin)
	N, _ := sc.NextInt()
	turns := make([]turn, N)
	for i := 0; i < N; i++ {
		turns[i].numbers[0], _ = sc.NextInt()
		turns[i].numbers[1], _ = sc.NextInt()
		turns[i].numbers[2], _ = sc.NextInt()
		turns[i].numbers[3], _ = sc.NextInt()
		turns[i].answer, _ = sc.Next()
	}

	fmt.Println(Solve(turns))
}

func Solve(turns []turn) int {
	const size = 10
	var status [size]bool
	for i := 0; i < size; i++ {
		status[i] = true
	}
	for _, turn := range turns {
		if turn.answer == "NO" {
			for _, v := range turn.numbers {
				status[v] = false
			}
		} else {
			var check [size]bool
			for _, v := range turn.numbers {
				check[v] = true
			}
			for i := 0; i < size; i++ {
				status[i] = status[i] && check[i]
			}
		}
	}
	for i := 0; i < size; i++ {
		if status[i] {
			return i
		}
	}
	return -1
}

type turn struct {
	numbers [4]int
	answer  string
}

type Scanner struct {
	*bufio.Scanner
}

func NewScanner(r io.Reader) *Scanner {
	return &Scanner{
		bufio.NewScanner(r),
	}
}

func (s *Scanner) Next() (string, error) {
	s.Scanner.Split(bufio.ScanWords)
	return s.nextToken()
}

func (s *Scanner) nextToken() (string, error) {
	sc := s.Scanner
	if sc.Scan() {
		return sc.Text(), nil
	}
	if sc.Err() != nil {
		return "", sc.Err()
	}
	return "", io.EOF
}

func (s *Scanner) NextInt() (int, error) {
	token, err := s.Next()
	if err != nil {
		return 0, err
	}
	return strconv.Atoi(token)
}