def activity_set(act_cs):
    """Return a set of ints from a comma-separated list of int strings.
    Attributes:
        act_cs (str) : comma-separated list of int strings
    Returns:
        set (int) : int's in the original string
    """
    ai_strs = [ai for ai in act_cs.split(",")]

    if ai_strs[-1] == "":
        ai_strs = ai_strs[:-1]

    if ai_strs[0] == ".":
        aset = set()
    else:
        aset = set([int(ai) for ai in ai_strs])

    return aset