#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>
using namespace std;


#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;
typedef unsigned long long ull;
typedef long double lb;
/* ここからが本編 */
int main(void)
{
   int i,j,k;
   ull n;
   int m;
   cin >> n >> m;
   n /= 1000;
   cout << (n/m)*1000 <<endl;
   return 0;
}