def distance(start, end):
    """Returns the distance between two points."""
    if start < 0 and end < 0:
        return abs(min(start, end) - max(start, end))
    elif start >= 0 and end >= 0:
        return max(start, end) - min(start, end)
    else:
        #  one neg, one pos
        return max(start, end) - min(start, end)