n = int(input())
line = set(input())
condition = 1
setNew = set()
while line != {'H', 'E', 'L', 'P'}:
yesOrNo = input()
if yesOrNo == 'YES' and condition == 1:
setNew = line
condition = 0
elif yesOrNo == 'YES':
setNew &= line
else:
setNew -= setNew & line
line = set(input())
print(' '.join(setNew))