package main

import "fmt"

func main() {
	var ok [10]bool
	for i := 0; i < len(ok); i++ {
		ok[i] = true
	}
	var a [4]int
	var N int
	fmt.Scan(&N)
	for i := 0; i < N; i++ {
		for j := 0; j < 4; j++ {
			fmt.Scan(&a[j])
		}
		var ans string
		fmt.Scan(&ans)
		if ans == "NO" {
			for j := 0; j < 4; j++ {
				ok[a[j]] = false
			}
		} else {
			for j := 0; j < 10; j++ {
				ng := true
				for k := 0; k < len(a); k++ {
					if a[k] == j {
						ng = false
					}
				}
				if ng {
					ok[j] = false
				}
			}
		}
	}
	for i := 0; i < len(ok); i++ {
		if ok[i] {
			fmt.Println(i)
			return
		}
	}
}