N = int(input())
a = N+1
b = a/2
if N % 2 != 0:
  print(b/N)
else:
  print(0.5) N = int(input()) N int(input()) int input() input a = N+1 a N+1 N 1 b = a/2 b a/2 a 2 if N % 2 != 0:
  print(b/N)
else:
  print(0.5) N % 2 != 0 N % 2 N 2 0 print(b/N) print b/N b N print(0.5) print 0.5 N = int(input()) int(input()) N a = N+1 N+1 a b = a/2 a/2 b
N = int(input())
a = N+1
b = a/2
if N % 2 != 0:
  print(b/N)
else:
  print(0.5)