import java.util.*;
import java.util.stream.*;
import java.math.*;
class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  }
} import java.util.*; util.* java import java.util.stream.*; stream.* java.util import java.math.*; math.* java class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  } main {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal A = new BigDecimal(sc.next()); A new BigDecimal(sc.next()) BigDecimal B = new BigDecimal(sc.next()); B new BigDecimal(sc.next()) System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN)) System.out.println System.out System System.out A.multiply(B).setScale(0, RoundingMode.DOWN) A.multiply(B).setScale A.multiply(B) A.multiply A B 0 RoundingMode.DOWN RoundingMode RoundingMode.DOWN String[] args args
import java.util.*;
import java.util.stream.*;
import java.math.*;
class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  }
}
