s = input()
z = s.count('0')
o = s.count('1')
n = len(s)
chk = [True] * n
cnt = 0
for i in range(0, n):
if cnt == o // 2:
break
if s[i] == '1':
chk[i] = False
cnt += 1
cnt = 0
for i in range(n - 1, -1, -1):
if cnt == z // 2:
break
if s[i] == '0':
chk[i] = False
cnt += 1
for i in range(n):
if chk[i]:
print(end=s[i])