package main

import "fmt"

func main() {
	var N int
	fmt.Scan(&N)
	var bits int
	for i := 0; i < 10; i++ {
		bits |= (1 << uint(i))
	}
	for i := 0; i < N; i++ {
		var a, b, c, d int
		var ans string
		fmt.Scan(&a, &b, &c, &d, &ans)
		mask := (1 << uint(a)) | (1 << uint(b)) | (1 << uint(c)) | (1 << uint(d))
		if ans == "YES" {
			bits &= mask
		} else {
			bits &= ^mask
		}
	}
	for i := 0; i < 10; i++ {
		if (bits & (1 << uint(i))) != 0 {
			fmt.Println(i)
			return
		}
	}
}