import java.util.*;
import java.io.*;

public class Test{
  public static void main(String[] args)throws Exception{
      BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
      long min=1000;
      long M=Long.parseLong(br.readLine());
      long N=Long.parseLong(br.readLine());
      long a=M/min;
      a/=N;
      a*=min;
      System.out.println(a);
  }
}