function power( b : number; e : integer ) : number;
	begin
	if e<0 then	power := 1/power(b,-e)
	else if e=0 then	power := 1
	else if e=1 then	power := b
	else if (e mod 2) = 0 then
			power := sqr( power( b, e div 2 ) )
	else		power := sqr( power( b, e div 2 ) ) * b
	end;