using System;
using System.Collections.Generic;

class Program
{
    static string InputPattern = "Input4";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("10000");
            WillReturn.Add("5");
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("24000");
            WillReturn.Add("9");
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("1000");
            WillReturn.Add("6");
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        ulong N = ulong.Parse(InputList[0]);
        ulong M = ulong.Parse(InputList[1]);

        ulong Answer = N / (1000 * M) * 1000;
        Console.WriteLine(Answer);
    }
}