import math
N = float(input())
if(N%2==0):
  print(1/2)
else:
  print((math.floor(N/2)+1)/N) import math math N = float(input()) N float(input()) float input() input if(N%2==0):
  print(1/2)
else:
  print((math.floor(N/2)+1)/N) N%2==0 N%2 N 2 0 print(1/2) print 1/2 1 2 print((math.floor(N/2)+1)/N) print (math.floor(N/2)+1)/N math.floor(N/2)+1 math.floor(N/2) math.floor math floor N/2 N 2 1 N N = float(input()) float(input()) N
import math
N = float(input())
if(N%2==0):
  print(1/2)
else:
  print((math.floor(N/2)+1)/N)