"""
from math import gcd
from itertools import accumulate, combinations, permutations, product
from bisect import bisect, bisect_left
from collections import Counter, defaultdict, deque
from heapq import heappush, heappop
from functools import reduce
from operator import add, mul, sub, truediv, floordiv, mod

from decimal import *
getcontext().prec = 500

import string
ascii = string.ascii_lowercase
"""

import sys


def main():
    sys.setrecursionlimit(100000)
    sys.set_int_max_str_digits(100000)
    input = lambda: sys.stdin.readline()[:-1]
    N = int(input())

    n = 10**N
    d, m = divmod(n // 7, n)
    if m:
        ans = "".join([str(d), ".", str(m)])
    else:
        ans = str(d)
    print(ans)


if not __debug__:
    f = open(sys.argv[1], "r")
    sys.stdin = f

main()