# -*- coding: utf-8 -*-
"""
No.428 小数から逃げる夢
https://yukicoder.me/problems/no/428

"""
import sys
from sys import stdin
input = stdin.readline


def solve(digits, N):
    res = []
    C = 0                       # 桁上がり

    for d in digits[::-1]:
        if d == '.':
            break
        t = int(d) * N + C
        cd = t % 10
        res.append(cd)
        C = (t - cd) // 10

    if C == 0:
        res.append('.')
        res.append('0')
    else:
        res.append('.')
        while C > 0:
            res.append(C % 10)
            C //= 10

    res.reverse()
    return ''.join(map(str, res))


def main(args):
     D = '0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991'
     digits = list(D)
     N = int(input())
     ans = solve(digits, N)
     print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])