# -*- coding: utf-8 -*-
"""
No.285 消費税２
https://yukicoder.me/problems/no/285

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


def main(args):
    D = int(input())
    getcontext().prec = 15
    ans = Decimal(D) * Decimal(1.08)
    print('{:f}'.format(ans))
    # print(D + D * 0.08)


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