def next_bigger(n):
    # get number as digits in list
    digits = [int(x) for x in list(str(n))]

    # find index of pivot. return -1 if there is no pivot, meaning number is alreadig biggest
    pivot = -1
    for i in range(1, len(digits)):
        if digits[-i] > digits[-i - 1]:
            pivot = -i - 1
            break

    if pivot == -1:
        return -1

    # find the smallest digit to the right that is bigger than the pivot
    right = digits[pivot + 1 :]
    swap = right.index(min([x for x in right if x > digits[pivot]]))

    # swap pivot with found digit
    digits[pivot], digits[len(digits) - len(right) + swap] = (
        right[swap],
        digits[pivot],
    )

    # sort right side of new swapped pivot and replace it at the end
    right = digits[pivot + 1 :]
    right.sort()
    digits[pivot + 1 :] = right

    # return number
    return int("".join([str(x) for x in digits]))