2S  15-18 5422(4 H)/6322/7222
    2N  問牌型, GF
        3C    6223 or 6232 or 7222, MIN
             (3D=繼續問, then 3H/S/N=6223/6232/7222)
        3D    5422, MIN
        3H    5422, not MIN
        3S    6223, not MIN
        3N    6232, not MIN
        4H    7222, not MIN
    3m  to play
    3H  inv to 4H/3NT
    3S  inv
    3N  to play
    4m  STR m ST
    4H  to play
    4S  to play