#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define ITER(c)             __typeof__((c).begin())
#define FOREACH(it, c)      for (ITER(c) it=(c).begin(); it != (c).end(); ++it)
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
#define RREP(i, n)          for(int(i)=(n)-1;(i)>=0;--(i))
const int MOD = (int)1e9+7;

ll N,M,W,H;

int main(){
    cin >> N >> M;
    cout << N/1000/M*1000 << endl;
}