using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    public void Solve()
    {
        string[] NGV = Console.ReadLine().Split(' ');
        decimal N = decimal.Parse(NGV[0]);
        decimal G = decimal.Parse(NGV[1]);
        decimal V = decimal.Parse(NGV[2]);

        Console.WriteLine(Math.Floor(N / 5) * G / V);
    }

    static void Main()
    {
        var solver = new Program();
        solver.Solve();
    }
}