X = input()
l = list(map(int,list(X)))
s = set(l)
N = len(l)
import sys

if len(s) == 1:
    print(-1)
    exit()
l.sort(reverse = True)
u = N - 1
while l[u] == l[-1]:
    u -= 1
l[u],l[-1] = l[-1],l[u]
if l[0] == 0:
    print(-1)
    exit()
for i in l:
    print(i,end = "")
print()