def biggerIsGreater(w):
    # i is the index of the element on the right hand-side
    index = None
    for i in range(len(w)-1, -1, -1): 
        w_list = sorted(list(w[i:]))
        w_list.reverse()
        sorted_w = ""
        for char in w_list:
            sorted_w += char
        if sorted_w != w[i:]:
            index = i
            break
    
    if index is None:
        return "no answer"
    
    smallest_bigger = None
    for i in w[index:]:
        if i > w[index] and (smallest_bigger is None or i < smallest_bigger):
            smallest_bigger = i
    w_list = list(w[index + 1:])
    w_list.remove(smallest_bigger)
    w_list.append(w[index])
    w_list.sort()
    sorted_w = ""
    for char in w_list:
        sorted_w += char
    w = w[:index] + smallest_bigger + sorted_w
    return w