import java.math.BigDecimal;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	}
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	} main {
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal()); a new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal()) new BigDecimal(sc.nextBigInteger()).multiply new BigDecimal(sc.nextBigInteger()) sc.nextBigDecimal() sc.nextBigDecimal sc System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN)) System.out.println System.out System System.out a.setScale(0, BigDecimal.ROUND_DOWN) a.setScale a 0 BigDecimal.ROUND_DOWN BigDecimal BigDecimal.ROUND_DOWN String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	}
} Main
import java.math.BigDecimal;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		// 整数の入力
		BigDecimal a = new BigDecimal(sc.nextBigInteger()).multiply(sc.nextBigDecimal());
        System.out.println(a.setScale(0, BigDecimal.ROUND_DOWN));
	}
}