using System;

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var g = int.Parse(line[1]);
        var v = int.Parse(line[2]);
        var buygas = (long)g * (n / 5);
        var ans = (double)buygas / v;
        Console.WriteLine(ans);
    }
}