# -*- coding: utf-8 -*-
"""
No.379 五円硬貨
https://yukicoder.me/problems/no/379

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


def main(args):
    N, G, V = map(int, input().split())
    getcontext().prec = 30
    ans = Decimal(G * (N // 5)) / Decimal(V)
    print(ans)


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