#
#	A(t) =  A(t0) * exp((-1) * ln(2)*(t-t0)/Thalftime) 
#
	diffdatetime.d		Doba,t0,t
	mulf                    Doba,0.6931,D
	divf                    D,Polocas,X
	mulf                    X,-1,Y
	exp                     Y,E
	mulf                    A0,E,AT
	trunc.number            AT
	return