str = input()
dic = {}
res = ''
# set() 是为了减少循环次数
for s in set(str):
cnt = str.count(s)
dic[s] = cnt
for d in str :
idx = min(dic.values())
if dic[d] != idx :
res += d
print (res)
str = input()
dic = {}
res = ''
# set() 是为了减少循环次数
for s in set(str):
cnt = str.count(s)
dic[s] = cnt
for d in str :
idx = min(dic.values())
if dic[d] != idx :
res += d
print (res)