import java.math.BigDecimal;
import java.math.RoundingMode;
import 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	}

} import java.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.*; util.* java 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	}

} 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	} main {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = sc.nextLong(); a sc.nextLong() sc.nextLong sc double b = sc.nextDouble(); b sc.nextDouble() sc.nextDouble sc BigDecimal bd = new BigDecimal(String.valueOf(a)); bd new BigDecimal(String.valueOf(a)) BigDecimal bd1 = new BigDecimal(String.valueOf(b)); bd1 new BigDecimal(String.valueOf(b)) BigDecimal bd2 = bd1.multiply(bd); bd2 bd1.multiply(bd) bd1.multiply bd1 bd BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN); bd3 bd2.setScale(0, RoundingMode.DOWN) bd2.setScale bd2 0 RoundingMode.DOWN RoundingMode RoundingMode.DOWN System.out.println(bd3) System.out.println System.out System System.out bd3 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	}

} 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	}

} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import 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);
		long a = sc.nextLong();
		double b = sc.nextDouble();
		
		BigDecimal bd = new BigDecimal(String.valueOf(a));
		BigDecimal bd1 = new BigDecimal(String.valueOf(b));
		BigDecimal bd2 = bd1.multiply(bd);
		BigDecimal bd3 = bd2.setScale(0, RoundingMode.DOWN);
		
		System.out.println(bd3);
	}

}