//package hoge; のようなパッケージ宣言は提出前に除く
//インポート文など
import java.util.Scanner;
import java.math.BigDecimal;
public class Main { //クラス名はMain
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    }
} import java.util.Scanner; Scanner java.util import java.math.BigDecimal; BigDecimal java.math public class Main { //クラス名はMain
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    }
} Main public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    } main {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) String a = in.next(); a in.next() in.next in String b = in.next(); b in.next() in.next in BigDecimal c = new BigDecimal(a); c new BigDecimal(a) BigDecimal d = new BigDecimal(b); d new BigDecimal(b) BigDecimal e = c.multiply(d); e c.multiply(d) c.multiply c d BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN); f e.setScale(0, BigDecimal.ROUND_DOWN) e.setScale e 0 BigDecimal.ROUND_DOWN BigDecimal BigDecimal.ROUND_DOWN System.out.println(f) System.out.println System.out System System.out f String[] args args public class Main { //クラス名はMain
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    }
} public class Main { //クラス名はMain
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    }
} Main
//package hoge; のようなパッケージ宣言は提出前に除く
//インポート文など
import java.util.Scanner;
import java.math.BigDecimal;
public class Main { //クラス名はMain
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
      	String a = in.next();
        String b = in.next();
      	BigDecimal c = new BigDecimal(a);
        BigDecimal d = new BigDecimal(b);
        BigDecimal e = c.multiply(d);
        BigDecimal f = e.setScale(0, BigDecimal.ROUND_DOWN);
        System.out.println(f);      	
    }
}