#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);

int dp[11000] = {1};

int main()
{
    ll n,m;
    cin >> n >> m;
    cout << n/1000/m*1000 << endl;
    return 0;
}