import kotlin.math.*

fun main(args: Array<String>) {

    val N = readLine()!!.toInt()
    val flags = IntArray(10) {-1}
    for (i in 1..N) {
        val ln = readLine()!!.split(" ")
        val yes = ln[4] == "YES"
        val abcd = arrayOf(ln[0].toInt(), ln[1].toInt(), ln[2].toInt(), ln[3].toInt())
        if (yes) {
            for (j in 0..9) {
                if (j in abcd) {
                    if (flags[j] == -1) {
                        flags[j] = 1
                    }
                } else {
                    flags[j] = 0
                }
            }
        } else {
            for (j in 0..3) {
                flags[abcd[j]] = 0
            }        
        }
            
    }
    for (i in 0..9) {
        if (flags[i] == 1 || flags[i] == -1) {
            println(i)
            return
        }
    }
}