X = [int(i) for i in list(input())]

X.sort(reverse=True)

if X[0] == 0 or X[0] == X[-1]:
    print(-1)
else:
    S = "".join(map(str, X))
    T = S[:-2] + S[-1] + S[-2]
    print(T if T[0] != "0" else -1)