a=int(input())
if a%2==0:
  print(1/2)
else:
  print(((a+1)/2)/a) a=int(input()) a int(input()) int input() input if a%2==0:
  print(1/2)
else:
  print(((a+1)/2)/a) a%2==0 a%2 a 2 0 print(1/2) print 1/2 1 2 print(((a+1)/2)/a) print ((a+1)/2)/a (a+1)/2 a+1 a 1 2 a a=int(input()) int(input()) a
a=int(input())
if a%2==0:
  print(1/2)
else:
  print(((a+1)/2)/a)