XE XB XA IA
= 2 lower beds & 2 upper beds / 
= double bed / 
= double bed & sofa / 
= 1 double bed & 1 upper bed / 
= 2 lower beds
XE XB XA IA
= 2 lower beds & 2 upper beds / = double bed / = double bed & sofa / = 1 double bed & 1 upper bed / = 2 lower beds