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

/**
 * https://atcoder.jp/contests/abc169/tasks/abc169_c
 * Multiplication 3
 */
public class Main {
	public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	}
} import java.math.BigDecimal; BigDecimal java.math import java.math.BigInteger; BigInteger java.math import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	}
} Main public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	} main {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	} try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		} {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		} Scanner sc= new Scanner(System.in) Scanner sc= new Scanner(System.in) new Scanner(System.in) BigDecimal a = BigDecimal.valueOf(sc.nextLong()); a BigDecimal.valueOf(sc.nextLong()) BigDecimal.valueOf BigDecimal sc.nextLong() sc.nextLong sc BigDecimal b = BigDecimal.valueOf(sc.nextDouble()); b BigDecimal.valueOf(sc.nextDouble()) BigDecimal.valueOf BigDecimal sc.nextDouble() sc.nextDouble sc BigInteger ans = a.multiply(b).toBigInteger(); ans a.multiply(b).toBigInteger() a.multiply(b).toBigInteger a.multiply(b) a.multiply a b System.out.println(ans) System.out.println System.out System System.out ans String...args args public class Main {
	public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	}
} public class Main {
	public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	}
} Main
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Scanner;

/**
 * https://atcoder.jp/contests/abc169/tasks/abc169_c
 * Multiplication 3
 */
public class Main {
	public static void main(String...args) {
		try (Scanner sc= new Scanner(System.in)) {
			BigDecimal a = BigDecimal.valueOf(sc.nextLong());
			BigDecimal b = BigDecimal.valueOf(sc.nextDouble());
			BigInteger ans = a.multiply(b).toBigInteger();
			System.out.println(ans);
		}
	}
}