public class Main {

    static java.util.Scanner scan = new java.util.Scanner(System.in);

    public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    }

    public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    }

    public static String line(){
        return scan.nextLine();
    }

    public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    }

    public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    }

    public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    }

    public static void puts(Object a){
        System.out.println(a);
    }

    public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    }
} public class Main {

    static java.util.Scanner scan = new java.util.Scanner(System.in);

    public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    }

    public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    }

    public static String line(){
        return scan.nextLine();
    }

    public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    }

    public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    }

    public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    }

    public static void puts(Object a){
        System.out.println(a);
    }

    public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    }
} Main static java.util.Scanner scan = new java.util.Scanner(System.in); scan new java.util.Scanner(System.in) public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    } pow {
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    } int b = 1; b 1 for(int i = 0; i < a;i++){
            b *= 10;
        } int i = 0; int i = 0; i 0 i < a i a i++ i++ i {
            b *= 10;
        } {
            b *= 10;
        } b *= 10 b 10 return b; b int a a public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    } main {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    } String[] line = line().split(" "); line line().split(" ") line().split line() line " " String[] sliced_period = line[1].split("\\."); sliced_period line[1].split("\\.") line[1].split line[1] line 1 "\\." Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])}; vars new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])} Long first = vars[0]; first vars[0] vars 0 Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2]; second (vars[1] * (pow(sliced_period[1].length())))+vars[2] (vars[1] * (pow(sliced_period[1].length()))) vars[1] vars 1 (pow(sliced_period[1].length())) pow sliced_period[1].length() sliced_period[1].length sliced_period[1] sliced_period 1 vars[2] vars 2 Long calc = first * second; calc first * second first second String parse = String.valueOf(calc).split("\\.")[0]; parse String.valueOf(calc).split("\\.")[0] String.valueOf(calc).split("\\.") String.valueOf(calc).split String.valueOf(calc) String.valueOf String calc "\\." 0 if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        } parse.length() - sliced_period[1].length() <= 0 parse.length() - sliced_period[1].length() parse.length() parse.length parse sliced_period[1].length() sliced_period[1].length sliced_period[1] sliced_period 1 0 {
            puts("0");
            return;
        } puts("0") puts "0" return; String floor = parse.substring(0,(parse.length())-sliced_period[1].length()); floor parse.substring(0,(parse.length())-sliced_period[1].length()) parse.substring parse 0 (parse.length())-sliced_period[1].length() (parse.length()) parse.length parse sliced_period[1].length() sliced_period[1].length sliced_period[1] sliced_period 1 puts(floor) puts floor scan.close() scan.close scan String[] args args public static String line(){
        return scan.nextLine();
    } line {
        return scan.nextLine();
    } return scan.nextLine(); scan.nextLine() scan.nextLine scan public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    } lineInts {
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    } String l = line(); l line() line String[] l1 = l.split(" "); l1 l.split(" ") l.split l " " int[] a = new int[l1.length]; a new int[l1.length] l1.length l1 l1.length for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        } int i = 0; int i = 0; i 0 i < l1.length i l1.length l1 l1.length i++ i++ i {
            a[i] = Integer.parseInt(l1[i]);
        } {
            a[i] = Integer.parseInt(l1[i]);
        } a[i] = Integer.parseInt(l1[i]) a[i] a i Integer.parseInt(l1[i]) Integer.parseInt Integer l1[i] l1 i return a; a public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    } split_piriod_Ints {
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    } String l = line(); l line() line int[] b = new int[a.length]; b new int[a.length] a.length a a.length for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        } int i = 0; int i = 0; i 0 i < a.length i a.length a a.length i++ i++ i {
            b[i] = Integer.parseInt(a[i]);
        } {
            b[i] = Integer.parseInt(a[i]);
        } b[i] = Integer.parseInt(a[i]) b[i] b i Integer.parseInt(a[i]) Integer.parseInt Integer a[i] a i return b; b String[] a a public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    } lineLongs {
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    } String l = line(); l line() line String[] l1 = l.split(" "); l1 l.split(" ") l.split l " " long[] a = new long[l1.length]; a new long[l1.length] l1.length l1 l1.length for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        } int i = 0; int i = 0; i 0 i < l1.length i l1.length l1 l1.length i++ i++ i {
            a[i] = Long.parseLong(l1[i]);
        } {
            a[i] = Long.parseLong(l1[i]);
        } a[i] = Long.parseLong(l1[i]) a[i] a i Long.parseLong(l1[i]) Long.parseLong Long l1[i] l1 i return a; a public static void puts(Object a){
        System.out.println(a);
    } puts {
        System.out.println(a);
    } System.out.println(a) System.out.println System.out System System.out a Object a a public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    } puts {
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    } for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        } int i = 0; int i = 0; i 0 i<a.length i a.length a a.length i++ i++ i {
            System.out.println(a[i]);
        } {
            System.out.println(a[i]);
        } System.out.println(a[i]) System.out.println System.out System System.out a[i] a i Object... a a public class Main {

    static java.util.Scanner scan = new java.util.Scanner(System.in);

    public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    }

    public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    }

    public static String line(){
        return scan.nextLine();
    }

    public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    }

    public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    }

    public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    }

    public static void puts(Object a){
        System.out.println(a);
    }

    public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    }
} public class Main {

    static java.util.Scanner scan = new java.util.Scanner(System.in);

    public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    }

    public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    }

    public static String line(){
        return scan.nextLine();
    }

    public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    }

    public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    }

    public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    }

    public static void puts(Object a){
        System.out.println(a);
    }

    public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    }
} Main
public class Main {

    static java.util.Scanner scan = new java.util.Scanner(System.in);

    public static int pow(int a){
        int b = 1;
        for(int i = 0; i < a;i++){
            b *= 10;
        }
        return b;
    }

    public static void main(String[] args) {

        String[] line = line().split(" ");
        String[] sliced_period = line[1].split("\\.");

        Long[] vars = new Long[]{Long.parseLong(line[0]),Long.parseLong(sliced_period[0]),Long.parseLong(sliced_period[1])};

        Long first = vars[0];
        Long second = (vars[1] * (pow(sliced_period[1].length())))+vars[2];
        Long calc = first * second;
        String parse = String.valueOf(calc).split("\\.")[0];

        if(parse.length() - sliced_period[1].length() <= 0){
            puts("0");
            return;
        }

        String floor = parse.substring(0,(parse.length())-sliced_period[1].length());
        puts(floor);

        scan.close();
    }

    public static String line(){
        return scan.nextLine();
    }

    public static int[] lineInts(){
        String l = line();
        String[] l1 = l.split(" ");
        int[] a = new int[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Integer.parseInt(l1[i]);
        }
        return a;
    }

    public static int[] split_piriod_Ints(String[] a){
        String l = line();
        int[] b = new int[a.length];
        for(int i = 0; i < a.length; i++){
            b[i] = Integer.parseInt(a[i]);
        }
        return b;
    }

    public static long[] lineLongs(){
        String l = line();
        String[] l1 = l.split(" ");
        long[] a = new long[l1.length];
        for(int i = 0; i < l1.length; i++){
            a[i] = Long.parseLong(l1[i]);
        }
        return a;
    }

    public static void puts(Object a){
        System.out.println(a);
    }

    public static void puts(Object... a){
        for(int i = 0; i<a.length;i++){
            System.out.println(a[i]);
        }
    }
}
