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

public class yukicoder
{
    public static void Main()
    {
		double[] input = Console.ReadLine().Split(' ').Select(c => double.Parse(c)).ToArray();
		double n = input[0];
		double g = input[1];
		double v = input[2];
		
		Console.WriteLine(Math.Truncate(n / 5) * (g / v));

    }
}