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

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	}

} import java.math.BigDecimal; BigDecimal 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)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	}

} Main public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	} main {
		try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	} try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		} {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) String a = sc.next(); a sc.next() sc.next sc String b = sc.next(); b sc.next() sc.next sc BigDecimal bigA = new BigDecimal(a); bigA new BigDecimal(a) BigDecimal bigB = new BigDecimal(b); bigB new BigDecimal(b) BigDecimal c = bigA.multiply(bigB); c bigA.multiply(bigB) bigA.multiply bigA bigB long ans = c.longValue(); ans c.longValue() c.longValue c 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)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	}

} public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	}

} Main
import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			String a = sc.next();
			String b = sc.next();
			
			BigDecimal bigA = new BigDecimal(a);
			BigDecimal bigB = new BigDecimal(b);
			
			
			BigDecimal c = bigA.multiply(bigB);
			
			long ans = c.longValue();
			
			System.out.println(ans);
		}
	}

}