def GetGuestName(sHostGuestStepName):
	"""Get the guest name from the given formal HOST_GUEST_StepSize name, e.g. GEDKUY_ethene_S0-4.
	[sHostGuestStepName]: string, formal sHostGuestStepName name.
	<retval>: string, guest name.
	"""
	iAnchor= sHostGuestStepName.find("_")
	if iAnchor==-1:
		raise Exception(f"Failed finding first score in {sHostGuestStepName}")
	iAnchor+=1
	iScore= sHostGuestStepName.find("_",iAnchor)
	if iScore==-1:
		raise Exception(f"Failed finding second score in {sHostGuestStepName}")
	return sHostGuestStepName[iAnchor:iScore]