while True:
try:
string = input()
dictionary = {}
for i in string:
if i not in dictionary:
dictionary[i] = 1
else:
dictionary[i] += 1
min_num = sorted(dictionary.values())[0]
nlist = []
for i in dictionary.keys():
if dictionary[i] == min_num:
nlist.append(i)
result = ''
for i in string:
if i in nlist:
continue
else:
result += i
print(result)
except EOFError:
break