// remove more clutter
  #define O printf
  #define R return
  #define Z static
  #define P(x,y) {if(x)R(y);}
  #define U(x) P(!(x),0)
  #define SW switch
  #define CS(n,x)	case n:x;break;
  #define CD default

Thanks for that. The comment makes it classic.