import java.io.InputStream;
import java.io.PrintStream;
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  }
} import java.io.InputStream; InputStream java.io import java.io.PrintStream; PrintStream java.io import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  }
} Main public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  } main {
    solve(System.in, System.out);
  } solve(System.in, System.out) solve System.in System System.in System.out System System.out String[] args args static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  } solve {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  } Scanner scan = new Scanner(is); scan new Scanner(is) long A = scan.nextLong(); A scan.nextLong() scan.nextLong scan Double B = scan.nextDouble(); B scan.nextDouble() scan.nextDouble scan BigDecimal BB = new BigDecimal(B.toString()); BB new BigDecimal(B.toString()) BigDecimal BD = BB.multiply(new BigDecimal(A)); BD BB.multiply(new BigDecimal(A)) BB.multiply BB new BigDecimal(A) os.println(BD.longValue()) os.println os BD.longValue() BD.longValue BD InputStream is is PrintStream os os public class Main {
  public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  }
} public class Main {
  public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  }
} Main
import java.io.InputStream;
import java.io.PrintStream;
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) throws Exception {
    solve(System.in, System.out);
  }

  static void solve(InputStream is, PrintStream os) {
    // Your code here!
    Scanner scan = new Scanner(is);
    long A = scan.nextLong();
    Double B = scan.nextDouble();
    BigDecimal BB = new BigDecimal(B.toString());
    BigDecimal BD = BB.multiply(new BigDecimal(A));

    os.println(BD.longValue());
  }
}
