import itertools

def calc(lst):
  M = ''
  for i in itertools.permutations(lst, r = len(lst)):
    if M == '':
      M = ''.join(i)
    else:
      tmp = ''.join(i)
      if M != tmp:
        return tmp
  else:
    return '0'

X = input().strip()

X = sorted(list(X), reverse=True)

ans = calc(X)

if ans[0] == '0':
  ans = '-1'

print(ans)