def sw(s):
  l=[int(i) for i in s]
  if l==sorted(l,reverse=True):
    return s
  s=sorted(set(l),reverse=True)
  
  n=len(l)
  for i in range(1,n):
    m=max(l[i-n:])
    if l[i-1]<m:
      a=(i-1)
      r=[z for z in reversed(l)]
      b=(-1-r.index(m))
      l[a],l[b]=l[b],l[a]
      return ''.join(list(map(str,l)))
  return s
print(sw(input()))