n=int(input())
if n%2==1:
  x=((n//2)+1)/n
  print(x)
  
else:
  print(1/2) n=int(input()) n int(input()) int input() input if n%2==1:
  x=((n//2)+1)/n
  print(x)
  
else:
  print(1/2) n%2==1 n%2 n 2 1 x=((n//2)+1)/n x ((n//2)+1)/n (n//2)+1 n//2 n 2 1 n print(x) print x print(1/2) print 1/2 1 2 x=((n//2)+1)/n ((n//2)+1)/n x n=int(input()) int(input()) n
n=int(input())
if n%2==1:
  x=((n//2)+1)/n
  print(x)
  
else:
  print(1/2)
