import collections

x = int(input())

x_list = list(str(x))
x_list = [int(e) for e in x_list]
sorted_x = sorted(x_list, reverse=True)

if len(sorted_x) == 2:
    if sorted_x[1] == 0 or sorted_x[0] == sorted_x[1]:
        res = -1
    else:
        res = int(str(sorted_x[1]) + str(sorted_x[0]))
elif len(sorted_x) > 2:
    sorted_x_clc = collections.Counter(sorted_x)
    if len(sorted_x_clc.keys()) == 1:
        res = -1
    else:
        sorted_x_clc_back = collections.Counter(sorted_x[1:])
        if len(sorted_x_clc_back.keys()) == 1:
            sorted_x[0], sorted_x[1] \
            = sorted_x[1], sorted_x[0]
        else:
            last_index_max = \
            (len(sorted_x) - 1) - sorted(sorted_x[1:]).index(max(sorted_x[1:]))
            sorted_x[last_index_max], sorted_x[last_index_max + 1] = \
            sorted_x[last_index_max + 1], sorted_x[last_index_max]
        res = ''.join([str(e) for e in sorted_x])
        
print(res)