X = list(input())
X.sort(reverse = True)
if X[1] == '0' or X[0] == X[-1]:
    print(-1)
    exit()

for i in range(len(X)-1,0,-1):
    if X[i] != X[i-1]:
        X[i],X[i-1] = X[i-1],X[i]
        break

for i in X:
    print(i,end="")
print()