#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef string str;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    ll n, k;
    cin >> n >> k;
    ll i = 0, countt = 0;
    while ((i+1) * 1000 * k <= n)
    {
        countt++;
        i++;
    }
    if (countt == 0) cout << 0;
    else cout << i * 1000;
    return 0;
}