real function distsub(a,b,n)

	implicit none

	integer i, n
	real*8    a(n), b(n)
	
	distsub=(a(1)-b(1))**2
	do i=2,n
	 distsub=distsub+(a(i)-b(i))**2
	enddo
	distsub=sqrt(distsub)
	
	return
	end