N=int(input())
if N==0:
  print(0)
else:
  num=142857
  times=N//6
  r=N%6
  lst=['1','4','2','8','5','7']
  ans='0.'+str(num)*times
  if r==0:
    print(ans)
  else:
    for i in range(0,r):
      ans+=lst[i]
    print(ans)