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

public class Main {	

	private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	}
	
	//Switch input source (stdin/file)
	private static BufferedReader br;
	public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	}

	//Input read utility
	private static StringTokenizer tokenizer = null;
	public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}
	//Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	}
	//Get next single long
	private static long nl() {
		return Long.parseLong(next());
	}
	//Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	}
	//Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	//Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	}
	//Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}
} import java.util.*; util.* java import java.io.*; io.* java import java.math.BigInteger; BigInteger java.math public class Main {	

	private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	}
	
	//Switch input source (stdin/file)
	private static BufferedReader br;
	public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	}

	//Input read utility
	private static StringTokenizer tokenizer = null;
	public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}
	//Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	}
	//Get next single long
	private static long nl() {
		return Long.parseLong(next());
	}
	//Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	}
	//Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	//Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	}
	//Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}
} Main //Switch input source (stdin/file)
	private static BufferedReader br; br //Input read utility
	private static StringTokenizer tokenizer = null; tokenizer null private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	} solve {
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	} long A = nl(); A nl() nl char[] Bca = next().toCharArray(); Bca next().toCharArray() next().toCharArray next() next long B = 0; B 0 int dig = 2; dig 2 for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		} char c Bca {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		} {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		} if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			} c != '.' c '.' {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			} B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig) B (long)Character.getNumericValue(c) * (long)Math.pow(10, dig) (long)Character.getNumericValue(c) Character.getNumericValue Character c (long)Math.pow(10, dig) Math.pow Math 10 dig dig-- dig System.out.println(A*B/100L) System.out.println System.out System System.out A*B/100L A*B A B 100L public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	} main {
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	} br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String debugDataPath = System.getenv("DD_PATH"); debugDataPath System.getenv("DD_PATH") System.getenv System "DD_PATH" if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		} debugDataPath != null debugDataPath null {
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		} try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			} catch(Exception e){
				throw new RuntimeException(e);
			} Exception e {
				throw new RuntimeException(e);
			} throw new RuntimeException(e); new RuntimeException(e) {
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			} br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath)))) br new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath)))) boolean hasNext = true; hasNext true while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		} hasNext {
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		} solve() solve try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} catch(Exception e){
				throw new RuntimeException(e);
			} Exception e {
				throw new RuntimeException(e);
			} throw new RuntimeException(e); new RuntimeException(e) {
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			} br.mark(1) br.mark br 1 if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				} br.read() > 0 br.read() br.read br 0 {
					br.reset();			
					System.out.println("---");
				} br.reset() br.reset br System.out.println("---") System.out.println System.out System System.out "---" {
					hasNext = false;
				} hasNext = false hasNext false String[] args args public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	} next {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	} while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		} tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		} try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			} catch (Exception e) {
				throw new RuntimeException(e);
			} Exception e {
				throw new RuntimeException(e);
			} throw new RuntimeException(e); new RuntimeException(e) {
				tokenizer = new StringTokenizer(br.readLine());
			} tokenizer = new StringTokenizer(br.readLine()) tokenizer new StringTokenizer(br.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer //Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	} ni {
		return Integer.parseInt(next());
	} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next //Get next single long
	private static long nl() {
		return Long.parseLong(next());
	} nl {
		return Long.parseLong(next());
	} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next //Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	} nd {
		return Double.parseDouble(next());
	} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next //Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	} na {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	} int[] a = new int[n]; a new int[n] n for (int i = 0; i < n; i++)
			a[i] = ni(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = ni(); a[i] = ni() a[i] a i ni() ni return a; a int n n //Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	} ns {
		return next().toCharArray();
	} return next().toCharArray(); next().toCharArray() next().toCharArray next() next //Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	} nal {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	} long[] a = new long[n]; a new long[n] n for (int i = 0; i < n; i++)
			a[i] = nl(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nl(); a[i] = nl() a[i] a i nl() nl return a; a int n n public class Main {	

	private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	}
	
	//Switch input source (stdin/file)
	private static BufferedReader br;
	public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	}

	//Input read utility
	private static StringTokenizer tokenizer = null;
	public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}
	//Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	}
	//Get next single long
	private static long nl() {
		return Long.parseLong(next());
	}
	//Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	}
	//Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	//Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	}
	//Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}
} public class Main {	

	private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	}
	
	//Switch input source (stdin/file)
	private static BufferedReader br;
	public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	}

	//Input read utility
	private static StringTokenizer tokenizer = null;
	public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}
	//Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	}
	//Get next single long
	private static long nl() {
		return Long.parseLong(next());
	}
	//Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	}
	//Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	//Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	}
	//Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}
} Main
import java.util.*;
import java.io.*;
import java.math.BigInteger;

public class Main {	

	private static void solve(){
		//Implement solution here.
		long A = nl();
		char[] Bca = next().toCharArray();
		long B = 0;
		int dig = 2;
		for(char c:Bca) {
			if(c != '.') {
				B += (long)Character.getNumericValue(c) * (long)Math.pow(10, dig);
				dig--;
			}
		}
//		System.out.println(B);
//		System.out.println(A * B);
		System.out.println(A*B/100L);
	}
	
	//Switch input source (stdin/file)
	private static BufferedReader br;
	public static void main(String[] args){
		br = new BufferedReader(new InputStreamReader(System.in));
		String debugDataPath = System.getenv("DD_PATH");        
		if(debugDataPath != null){
			try{
				br = new BufferedReader(new InputStreamReader(new FileInputStream(new File(debugDataPath))));
			}catch(Exception e){
				throw new RuntimeException(e);
			}
		}
		boolean hasNext = true;
		while(hasNext){
			solve();	
			try{
				br.mark(1);
				if(br.read() > 0){
					br.reset();			
					System.out.println("---");
				} else {
					hasNext = false;
				}
			}catch(Exception e){
				throw new RuntimeException(e);
			} 
		}
	}

	//Input read utility
	private static StringTokenizer tokenizer = null;
	public static String next() {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(br.readLine());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	}
	//Get next single int
	private static int ni() {
		return Integer.parseInt(next());
	}
	//Get next single long
	private static long nl() {
		return Long.parseLong(next());
	}
	//Get next single double
	private static double nd() {
		return Double.parseDouble(next());
	}
	//Get next int array from one line
	private static int[] na(int n) {
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}
	//Get next char array from one line
	private static char[] ns() {
		return next().toCharArray();
	}
	//Get next long array from one line
	private static long[] nal(int n) {
		long[] a = new long[n];
		for (int i = 0; i < n; i++)
			a[i] = nl();
		return a;
	}
}
