n = int(input())
if n % 2 == 0:
  print(0.5)
else:
  print(((n+1)/(2*n))) n = int(input()) n int(input()) int input() input if n % 2 == 0:
  print(0.5)
else:
  print(((n+1)/(2*n))) n % 2 == 0 n % 2 n 2 0 print(0.5) print 0.5 print(((n+1)/(2*n))) print (n+1)/(2*n) n+1 n 1 2*n 2 n n = int(input()) int(input()) n
n = int(input())
if n % 2 == 0:
  print(0.5)
else:
  print(((n+1)/(2*n)))