import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		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.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		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) {
		// TODO 自動生成されたメソッド・スタブ
		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 {
		// TODO 自動生成されたメソッド・スタブ
		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 public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		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));
	}
} public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		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
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		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));
	}
}
