# 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.")