package main

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

const MaxInt = math.MaxInt64

var scanner *bufio.Scanner

const K = (1 << 10) - 1

func main() {
	flag := K
	var n int
	for fmt.Scanln(&n); n > 0; n-- {
		nums := make([]int, 4)
		for i := 0; i < 4; i++ {
			fmt.Scan(&nums[i])
		}
		var r string
		fmt.Scanln(&r)
		mask := 0
		for j := 0; j < 4; j++ {
			mask |= (1 << nums[j])
		}
		if r == "NO" {
			flag &= (K - mask)
		} else {
			flag &= mask
		}
	}
	for i := 0; i < 10; i++ {
		if flag&1 == 1 {
			fmt.Println(i)
			return
		}
		flag /= 2
	}
}

func init() {
	scanner = bufio.NewScanner(os.Stdin)
	scanner.Buffer([]byte{}, MaxInt)
	scanner.Split(bufio.ScanWords)
}

func Int() int {
	scanner.Scan()
	ret, _ := strconv.ParseInt(scanner.Text(), 10, 0)
	return int(ret)
}

func Ints(n int) []int {
	ret := make([]int, n)
	for i := 0; i < n; i++ {
		ret[i] = Int()
	}
	return ret
}

func Max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func Min(a, b int) int {
	if a < b {
		return a
	}
	return b
}