from collections import Counter


def main():
    X = input()
    counter_X = Counter(X)
    if counter_X["0"] == len(X) - 1:
        print(-1)
        return
    if len(counter_X) == 1:
        print(-1)
        return

    largest_X = "".join(sorted(list(X), key=int, reverse=True))

    swap_idx = -1
    while abs(swap_idx) < len(X):
        if largest_X[swap_idx] != largest_X[swap_idx-1]:
            break
        swap_idx -= 1

    second_large = list(largest_X)
    second_large[swap_idx], second_large[swap_idx-1] = (
        second_large[swap_idx-1], second_large[swap_idx]
    )
    print("".join(second_large))


if __name__ == "__main__":
    main()