def main():
    input_string = input()

    first_c = None
    first_w = None
    second_w = None

    for i, s in enumerate(input_string):
        if s == "c" and first_c is None:
            first_c = i
        if s == "w" and first_w is None and first_c is not None:
            first_w = i
        if s == "w" and second_w is None and first_c is not None and first_w is not None and first_w != i:
            second_w = i
    
    if any([first_c is None, first_w is None, second_w is None]):
        print(-1)
    else:
        print(second_w - first_c + 1)


if __name__ == "__main__":
    main()