b=1.
	a=0.
	n=1000
	dx=(b-a)/n
	sum=0.
	do i=1,n-1
	x=a+i*dx+dx/2.
	
	sum=sum+f(x)*dx
	enddo
	print*,sum
	stop
	end
	
	function f(x)
	f=x**2
	return
	end