using System;
using System.Linq;

class Program
{
    public void Solve()
    {
        decimal N = decimal.Parse(Console.ReadLine());
        int M = int.Parse(Console.ReadLine());

        Console.WriteLine(Math.Truncate(N / M / 1000) * 1000);
    }

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