A.500m B.253m C.899m D.699.5m
A.hAB=HB-HA B.hAB=HA-HB C.hAB=hA-hB D.HAB=HA-HB
A.HA+b=HB+a B.HA-a=HB-b C.hAB=HA-HB D.HA+a=HB+b