from collections import Counter
x = list(input())
ctr = Counter(x)
if len(ctr.keys()) - ctr['0'] <= 1:
    print(-1)
else:
    d = dict(sorted(ctr.items(), reverse=True))
    ret = ''    
    for k,v in d.items():
        ret += k*v
    for i in range(len(ret))[::-1]:
        if ret[i]!=ret[i-1]:
            ans = ret[:i-1]+ret[i]+ret[i-1]+ret[i+1:]
            break
    print(ans)