import java.util.*;
import java.math.*;
import java.text.*;

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        BigDecimal v = new BigDecimal(sc.next());
        BigDecimal t = new BigDecimal(sc.next());
        
        DecimalFormat df = new DecimalFormat();
        df.setMinimumFractionDigits(0);
        df.setMaximumFractionDigits(0);
        
        BigDecimal ret = v.multiply(t).setScale(0, BigDecimal.ROUND_DOWN);
        
        System.out.println(ret);
    }
}