import java.io.*;
import java.math.*;
import java.util.*;
import java.util.regex.*;


public class Main {

	final static long MOD = 1000000007;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static long cnt=0;
	public static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	}

	public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	}
	public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	}
	public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	}
	public static void solutionD(String[] args) throws Exception{

	}



	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}

}
 import java.io.*; io.* java import java.math.*; math.* java import java.util.*; util.* java import java.util.regex.*; regex.* java.util public class Main {

	final static long MOD = 1000000007;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static long cnt=0;
	public static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	}

	public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	}
	public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	}
	public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	}
	public static void solutionD(String[] args) throws Exception{

	}



	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}

} Main final static long MOD = 1000000007; MOD 1000000007 public static String[] Ws = null; Ws null public static int wsIndx = 0; wsIndx 0 public static BufferedReader in = null; in null public static long cnt=0; cnt 0 public static PrintWriter pw = new PrintWriter(System.out); pw new PrintWriter(System.out) public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	} main {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	} solutionC(args) solutionC args if(in!=null){
			in.close();
		} in!=null in null {
			in.close();
		} in.close() in.close in pw.flush() pw.flush pw pw.close() pw.close pw String[] args args public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	} solutionA {

		pw.println(nextInt()*nextInt());
	} pw.println(nextInt()*nextInt()) pw.println pw nextInt()*nextInt() nextInt() nextInt nextInt() nextInt String[] args args public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	} solutionB {
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	} int N = nextInt(); N nextInt() nextInt long[] a = nextLongs(); a nextLongs() nextLongs Arrays.sort(a) Arrays.sort Arrays a long ans = a[0]; ans a[0] a 0 for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		} int i=1; int i=1; i 1 i<N i N i++ i++ i {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		} {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		} long x = 0; x 0 try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			} catch(Exception e) {
				pw.println(-1);
				return;
			} Exception e {
				pw.println(-1);
				return;
			} pw.println(-1) pw.println pw -1 1 return; {
				x= Math.multiplyExact(ans, a[i]);
			} x= Math.multiplyExact(ans, a[i]) x Math.multiplyExact(ans, a[i]) Math.multiplyExact Math ans a[i] a i if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			} x>=1000000000000000001L x 1000000000000000001L {
				pw.println(-1);
				return;
			} pw.println(-1) pw.println pw -1 1 return; ans=x ans x pw.println(ans) pw.println pw ans String[] args args public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	} solutionC {
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	} String A = nextString(); A nextString() nextString String B = nextString(); B nextString() nextString BigDecimal bA = new BigDecimal(A); bA new BigDecimal(A) BigDecimal bB = new BigDecimal(B); bB new BigDecimal(B) pw.println(bA.multiply(bB).longValue()) pw.println pw bA.multiply(bB).longValue() bA.multiply(bB).longValue bA.multiply(bB) bA.multiply bA bB String[] args args public static void solutionD(String[] args) throws Exception{

	} solutionD {

	} String[] args args public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	} check {
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	} if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		} in == null in null {
			in = new BufferedReader(new InputStreamReader(System.in));
		} in = new BufferedReader(new InputStreamReader(System.in)) in new BufferedReader(new InputStreamReader(System.in)) if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		} Ws==null || Ws.length<=wsIndx Ws==null Ws null Ws.length<=wsIndx Ws.length Ws Ws.length wsIndx {
			Ws = in.readLine().split(" ");
			wsIndx=0;
		} Ws = in.readLine().split(" ") Ws in.readLine().split(" ") in.readLine().split in.readLine() in.readLine in " " wsIndx=0 wsIndx 0 public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	} nextInt {
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	} check() check return Integer.parseInt(Ws[wsIndx++]); Integer.parseInt(Ws[wsIndx++]) Integer.parseInt Integer Ws[wsIndx++] Ws wsIndx++ wsIndx public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	} nextLong {
		check();
		return Long.parseLong(Ws[wsIndx++]);
	} check() check return Long.parseLong(Ws[wsIndx++]); Long.parseLong(Ws[wsIndx++]) Long.parseLong Long Ws[wsIndx++] Ws wsIndx++ wsIndx public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	} nextString {
		check();
		return Ws[wsIndx++];
	} check() check return Ws[wsIndx++]; Ws[wsIndx++] Ws wsIndx++ wsIndx public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} nextInts {
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} check() check int[] tmp = new int[Ws.length]; tmp new int[Ws.length] Ws.length Ws Ws.length for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		} int i=0; int i=0; i 0 i<tmp.length i tmp.length tmp tmp.length i++ i++ i {
			tmp[i]=Integer.parseInt(Ws[i]);
		} {
			tmp[i]=Integer.parseInt(Ws[i]);
		} tmp[i]=Integer.parseInt(Ws[i]) tmp[i] tmp i Integer.parseInt(Ws[i]) Integer.parseInt Integer Ws[i] Ws i wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return tmp; tmp public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} nextLongs {
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} check() check long[] tmp = new long[Ws.length]; tmp new long[Ws.length] Ws.length Ws Ws.length for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		} int i=0; int i=0; i 0 i<tmp.length i tmp.length tmp tmp.length i++ i++ i {
			tmp[i]=Long.parseLong(Ws[i]);
		} {
			tmp[i]=Long.parseLong(Ws[i]);
		} tmp[i]=Long.parseLong(Ws[i]) tmp[i] tmp i Long.parseLong(Ws[i]) Long.parseLong Long Ws[i] Ws i wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return tmp; tmp public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	} nextStrings {
		check();
		wsIndx=Ws.length;
		return Ws;
	} check() check wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return Ws; Ws public class Main {

	final static long MOD = 1000000007;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static long cnt=0;
	public static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	}

	public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	}
	public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	}
	public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	}
	public static void solutionD(String[] args) throws Exception{

	}



	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}

} public class Main {

	final static long MOD = 1000000007;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static long cnt=0;
	public static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	}

	public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	}
	public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	}
	public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	}
	public static void solutionD(String[] args) throws Exception{

	}



	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}

} Main
import java.io.*;
import java.math.*;
import java.util.*;
import java.util.regex.*;


public class Main {

	final static long MOD = 1000000007;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static long cnt=0;
	public static PrintWriter pw = new PrintWriter(System.out);
	public static void main(String[] args) throws Exception {
		solutionC(args);
		if(in!=null){
			in.close();
		}
		pw.flush();
		pw.close();
	}

	public static void solutionA(String[] args) throws Exception{

		pw.println(nextInt()*nextInt());
	}
	public static void solutionB(String[] args) throws Exception{
		int N = nextInt();
		long[] a = nextLongs();
		Arrays.sort(a);
		long ans = a[0];
		for(int i=1;i<N;i++) {
			long x = 0;
			try{
				x= Math.multiplyExact(ans, a[i]);
			}catch(Exception e) {
				pw.println(-1);
				return;
			}
			if(x>=1000000000000000001L) {
				pw.println(-1);
				return;
			}
			ans=x;
		}
		pw.println(ans);
	}
	public static void solutionC(String[] args) throws Exception{
		String A = nextString();
		String B = nextString();
		BigDecimal bA = new BigDecimal(A);
		BigDecimal bB = new BigDecimal(B);



		pw.println(bA.multiply(bB).longValue());
	}
	public static void solutionD(String[] args) throws Exception{

	}



	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}

}

