using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukikoda
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] s = Console.ReadLine().Split();
            double N = double.Parse(s[0]);
            double G = double.Parse(s[1]);
            double V = double.Parse(s[2]);

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