#!/usr/bin/perl

use strict;
use warnings;

my $n = <>;
my $m = <>;

$n /= 1000;
my $ans = 0;

if($n < $m) {
	$n = 0;
} else {
	$n -= ($n % $m);
	$n /= $m;
	$n *= 1000;
}
print "$n\n";

exit;