N = int(input())

if(N % 2 == 0):
  print(0.5000000000)
else:
  M = (N+1)/2
  print(M/N) N = int(input()) N int(input()) int input() input if(N % 2 == 0):
  print(0.5000000000)
else:
  M = (N+1)/2
  print(M/N) N % 2 == 0 N % 2 N 2 0 print(0.5000000000) print 0.5000000000 M = (N+1)/2 M (N+1)/2 N+1 N 1 2 print(M/N) print M/N M N N = int(input()) int(input()) N M = (N+1)/2 (N+1)/2 M
N = int(input())

if(N % 2 == 0):
  print(0.5000000000)
else:
  M = (N+1)/2
  print(M/N)