import java.util.*;
import java.math.*;
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	}
} import java.util.*; util.* java import java.math.*; math.* java public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	}
} Main public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	} main {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String sa = sc.next(); sa sc.next() sc.next sc String sb = sc.next(); sb sc.next() sc.next sc BigDecimal A = new BigDecimal(sa); A new BigDecimal(sa) BigDecimal B = new BigDecimal(sb); B new BigDecimal(sb) System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN)) System.out.println System.out System System.out A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN) A.multiply(B).setScale A.multiply(B) A.multiply A B 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);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	}
} public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	}
} Main
import java.util.*;
import java.math.*;
public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		String sa = sc.next();
		String sb = sc.next();
		BigDecimal A = new BigDecimal(sa);
		BigDecimal B = new BigDecimal(sb);
		System.out.println(A.multiply(B).setScale(0, BigDecimal.ROUND_DOWN));
	}
}
