//#include <bits/stdc++.h>
#include <vector>
#include <string>
#include <queue>
#include <iostream>
#include <cstring>
#include <climits>
#define INF INT_MAX / 2
#define MOD 1000000007

using namespace std;

typedef pair<int,int> PII;
typedef pair<int,pair<int,int>> PIPII;
typedef long long ll;

int dx[] = {0,1,0,-1};
int dy[] = {1,0,-1,0};

int main(void) {    
    ll n,m;
    cin >> n >> m;
    n /= 1000;
    cout << n/m*1000 << endl;

    return 0;
}