X = [int(i) for i in input()]
X.sort()
s = True
for i in range(len(X)-1):
    if X[i] != X[i+1]:
        X[i],X[i+1] = X[i+1],X[i]
        s = False
        break
if s or X[-1] ==0:
    print(-1)
else:
    print("".join([str(i) for i in X[::-1]]))