X = list(input())
X.sort(reverse=True)
for i in range(len(X) - 2, -1, -1):
    if X[i] != X[i + 1]:
        X[i], X[i + 1] = X[i + 1], X[i]
        break
else:
    print(-1)
    exit()
        
if X[0] == "0":
    print(-1)
else:
    print(*X, sep="")