from optparse import OptionParser
from collections import defaultdict

def run(inputWord):
    a, states = open("avtomat.txt") ,defaultdict(list)
    state, final= a.readline().split()[1:],a.readline().split()[1:]
    [states[(i.split()[0], i.split()[1])].append(i.split()[3]) for i in a]
    for letter in inputWord:
        state = [st for s in state for st in states[(s,letter)]]
    return any(i in state for i in final)

print [(b,"YES") if run(b) else (b,"NO") for b in OptionParser().parse_args()[1]]

# avtomat.txt:
# init: q0
# final: q2 q3
# q0 a -> q1
# q0 b -> q3
# q1 a -> q1
# q1 b -> q2
# q2 a -> q2
# q2 b -> q2