a=0.0
b=1.0
n=200000
h=(b-a)/n
t=a
x=1.0
for k in range(n):
  xd=t-1/(1+x)
  #xdd=0.0
  xdd=1+xd/(1+x)**2
  x=x+h*xd+h**2*xdd/2.0
  t=t+h
print x