import math
def meteor(n):
	r = .09
	m=7 
	b=1.5e-3 
	x = 200.*1000
	v = -20.*1000
	H = 7.6*1000
	g = 9.8 # m/s2
	t_max = -x/v*10
	dt = t_max/n 
	for i in range(n):
	 dx = v*dt
	 x = x+dx 
	 if x<0.:
		 return v 
	 F = b*v**2*math.exp(-x/H)-m*g
	 a = F/m
	 dv = a*dt
	 v = v+dv
return -999