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

public class Main
{

    public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    }


    static FastReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    }
    
    
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static int ni()throws IOException{return Integer.parseInt(sc.next());}
    static long nl()throws IOException{return Long.parseLong(sc.next());}
    static double nd()throws IOException{return Double.parseDouble(sc.next());}
    static String nln()throws IOException{return sc.nextLine();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    
    static long mod=(long)1e9+7l;

    static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    }
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } 
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
} import java.util.*; util.* java import java.io.*; io.* java import java.math.*; math.* java public class Main
{

    public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    }


    static FastReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    }
    
    
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static int ni()throws IOException{return Integer.parseInt(sc.next());}
    static long nl()throws IOException{return Long.parseLong(sc.next());}
    static double nd()throws IOException{return Double.parseDouble(sc.next());}
    static String nln()throws IOException{return sc.nextLine();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    
    static long mod=(long)1e9+7l;

    static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    }
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } 
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
} Main static FastReader sc; sc static PrintWriter out; out static long mod=(long)1e9+7l; mod (long)1e9+7l (long)1e9 7l public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    } process {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    } String x=sc.next() x sc.next() sc.next sc y=sc.next(); y sc.next() sc.next sc BigDecimal a = new BigDecimal(x); a new BigDecimal(x) BigDecimal b = new BigDecimal(y); b new BigDecimal(y) a=a.multiply(b) a a.multiply(b) a.multiply a b a=a.setScale(0, RoundingMode.FLOOR) a a.setScale(0, RoundingMode.FLOOR) a.setScale a 0 RoundingMode.FLOOR RoundingMode RoundingMode.FLOOR pn(a.toString()) pn a.toString() a.toString a public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    } main {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    } out = new PrintWriter(System.out) out new PrintWriter(System.out) sc=new FastReader() sc new FastReader() long s = System.currentTimeMillis(); s System.currentTimeMillis() System.currentTimeMillis System int t=1; t 1 while(t-->0)
            process(); t-->0 t-- t 0 process() process out.flush() out.flush out System.err.println(System.currentTimeMillis()-s+"ms") System.err.println System.err System System.err System.currentTimeMillis()-s+"ms" System.currentTimeMillis()-s System.currentTimeMillis() System.currentTimeMillis System s "ms" String[]args args static void pn(Object o){out.println(o);} pn {out.println(o);} out.println(o) out.println out o Object o o static void p(Object o){out.print(o);} p {out.print(o);} out.print(o) out.print out o Object o o static int ni()throws IOException{return Integer.parseInt(sc.next());} ni {return Integer.parseInt(sc.next());} return Integer.parseInt(sc.next()); Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc static long nl()throws IOException{return Long.parseLong(sc.next());} nl {return Long.parseLong(sc.next());} return Long.parseLong(sc.next()); Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc static double nd()throws IOException{return Double.parseDouble(sc.next());} nd {return Double.parseDouble(sc.next());} return Double.parseDouble(sc.next()); Double.parseDouble(sc.next()) Double.parseDouble Double sc.next() sc.next sc static String nln()throws IOException{return sc.nextLine();} nln {return sc.nextLine();} return sc.nextLine(); sc.nextLine() sc.nextLine sc static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);} gcd {return (b==0)?a:gcd(b,a%b);} return (b==0)?a:gcd(b,a%b); (b==0)?a:gcd(b,a%b) (b==0) b 0 a gcd(b,a%b) gcd b a%b a b long a a long b b static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);} gcd {return (b==0)?a:gcd(b,a%b);} return (b==0)?a:gcd(b,a%b); (b==0)?a:gcd(b,a%b) (b==0) b 0 a gcd(b,a%b) gcd b a%b a b int a a int b b static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));} bit {return (n==0)?0:(1+bit(n&(n-1)));} return (n==0)?0:(1+bit(n&(n-1))); (n==0)?0:(1+bit(n&(n-1))) (n==0) n 0 0 (1+bit(n&(n-1))) 1 bit(n&(n-1)) bit n&(n-1) n (n-1) n 1 long n n static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    } r_sort {
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    } Random r = new Random(); r new Random() for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } int i = n-1; int i = n-1; i n-1 n 1 i > 0 i 0 i-- i-- i { 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } { 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } int j = r.nextInt(i+1); j r.nextInt(i+1) r.nextInt r i+1 i 1 T temp = arr[i]; temp arr[i] arr i arr[i] = arr[j] arr[i] arr i arr[j] arr j arr[j] = temp arr[j] arr j temp Arrays.sort(arr) Arrays.sort Arrays arr T arr[] arr int n n     static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } FastReader { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } next { 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st { 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } catch (IOException  e){ e.printStackTrace(); } IOException  e { e.printStackTrace(); } e.printStackTrace() e.printStackTrace e { st = new StringTokenizer(br.readLine()); } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } nextLine { 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } String str = ""; str "" try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } IOException e { e.printStackTrace(); } e.printStackTrace() e.printStackTrace e { str = br.readLine(); } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main
{

    public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    }


    static FastReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    }
    
    
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static int ni()throws IOException{return Integer.parseInt(sc.next());}
    static long nl()throws IOException{return Long.parseLong(sc.next());}
    static double nd()throws IOException{return Double.parseDouble(sc.next());}
    static String nln()throws IOException{return sc.nextLine();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    
    static long mod=(long)1e9+7l;

    static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    }
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } 
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
} public class Main
{

    public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    }


    static FastReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    }
    
    
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static int ni()throws IOException{return Integer.parseInt(sc.next());}
    static long nl()throws IOException{return Long.parseLong(sc.next());}
    static double nd()throws IOException{return Double.parseDouble(sc.next());}
    static String nln()throws IOException{return sc.nextLine();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    
    static long mod=(long)1e9+7l;

    static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    }
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } 
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
} Main
import java.util.*;
import java.io.*;
import java.math.*;

public class Main
{

    public static void process()throws IOException
    {
        String x=sc.next(),y=sc.next();
        BigDecimal a = new BigDecimal(x);
        BigDecimal b = new BigDecimal(y);
        a=a.multiply(b);
        a=a.setScale(0, RoundingMode.FLOOR);
        pn(a.toString());
    }


    static FastReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new FastReader();

        long s = System.currentTimeMillis();
        int t=1;
        //t=ni();
        while(t-->0)
            process();

        out.flush();
        System.err.println(System.currentTimeMillis()-s+"ms");
    }
    
    
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static int ni()throws IOException{return Integer.parseInt(sc.next());}
    static long nl()throws IOException{return Long.parseLong(sc.next());}
    static double nd()throws IOException{return Double.parseDouble(sc.next());}
    static String nln()throws IOException{return sc.nextLine();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    
    static long mod=(long)1e9+7l;

    static<T> void r_sort(T arr[],int n){
        Random r = new Random(); 
        for (int i = n-1; i > 0; i--){ 
            int j = r.nextInt(i+1); 
                  
            T temp = arr[i]; 
            arr[i] = arr[j]; 
            arr[j] = temp; 
        } 
        Arrays.sort(arr); 
    }
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ st = new StringTokenizer(br.readLine()); } catch (IOException  e){ e.printStackTrace(); } 
            } 
            return st.nextToken(); 
        } 
  
        String nextLine(){ 
            String str = ""; 
            try{ str = br.readLine(); } catch (IOException e) { e.printStackTrace(); } 
            return str; 
        } 
    } 
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
}
