import java.io.*;

// 処理
class Process {
    private long N;
    private int  M;

    Process(long N, int M) {
        this.N = N;
        this.M = M;
    }

    long getResult() {
        return (((N / M) / 1000) * 1000);
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        long N = Long.parseLong(bufferedReader.readLine().trim());

        int M = Integer.parseInt(bufferedReader.readLine().trim());

        // 出力
        printWriter.println((new Process(N, M)).getResult());

        bufferedReader.close();
        printWriter.close();
    }
}