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

namespace No128
{
	class MainClass
	{
		public static void Main (string[] args)
		{			
			var n = Console.ReadLine ().Split (' ').Select (v => Convert.ToInt64 (v)).ToArray ();
			var m = Console.ReadLine ().Split (' ').Select (v => Convert.ToInt64 (v)).ToArray ();

			var div = n[0] / m[0];
			var result = (div / 1000L) * 1000L;
			Console.WriteLine (result.ToString());
		}
	}
}