#include <iostream>
#include <limits>
using namespace std;
int main(){
    unsigned long long int n,m,ans;
    cin >> n >> m;
    
    if (n >= 10000){

    	ans = n/m; //予算÷人数
        ans = (ans/1000)*1000; //1000円以下切捨て
        cout << ans << endl;
    }else if (n < 1000){ //1000円以下の場合配布不可
    	cout << "0" << endl;
    }else{
    	ans = n/m;
        ans = (ans/1000)*1000;
        cout << ans << endl;
   	}
   return 0;
}