def main():
    turn=int(input())
    ans=([i for i in range(10)])
    for i in range(turn):
        taro=list(map(str,input().split()))
        if taro[4] == "NO":
            ans=[i for i in ans if i != int(taro[0]) and i != int(taro[1]) and i != int(taro[2]) and i != int(taro[3])]
    print(ans[0])

if __name__ == "__main__":
    main()