import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  }

  public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  }
} import java.math.BigDecimal; BigDecimal java.math import java.math.BigInteger; BigInteger java.math import java.math.RoundingMode; RoundingMode java.math import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.Collections; Collections java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {

  public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  }

  public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  }
} Main public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  } main {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  } abc169_c() abc169_c String[] args args public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  } abc169_c {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  } try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    } catch (Exception e) {
      System.out.println("エラー" + e);
    } Exception e {
      System.out.println("エラー" + e);
    } System.out.println("エラー" + e) System.out.println System.out System System.out "エラー" + e "エラー" e {
      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) Scanner sc = new Scanner(System.in) 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 public class Main {

  public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  }

  public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  }
} public class Main {

  public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  }

  public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  }
} Main
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    // printTestValue();
    // abc170_d();
    // abc169_b();
    abc169_c();
  }

  public static void abc169_c() {
    try (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));

    } catch (Exception e) {
      System.out.println("エラー" + e);
    }
  }
}