# Program to sum 1//2^n correct to 0.0001 accuracy

# N is the number of loop iterations
N = 50

# n is the loop  variable
n = 0
sum = 0.0

while n <= N :
  psum = sum
  sum = sum + (1.0/2.0)**n
  n = n + 1

  if sum-psum < 0.0001 :
     print(n, ' ' ,sum)
     break

  if n == N :
     print("Required accuracy not reached in ", N, "iterations.")