import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        int n, m, bill, cnt, ans;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();
        bill = 1000;
        
        cnt = n/(m*bill);
        if( cnt > 1 ){
            ans = cnt*bill;
        } else if( cnt == 1 ){
            ans = bill;
        } else {
            ans = 0;
        }
        
        System.out.println(ans);
    }
}