def main():
    N = int(input())
    
    yes = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
    no = []
    
    for i in range(N):
        s = input()
        if s[8] == 'N':
            no += list(map(int, s[0:7].split(' ')))
        else:
            yes += list(map(int, s[0:7].split(' ')))
    print(list(set(yes) - set(no))[0])

if __name__ == '__main__':
    main()