import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    } main {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc String strB = sc.next(); strB sc.next() sc.next sc int B_100 = Integer.parseInt(strB.replace(".", "")); B_100 Integer.parseInt(strB.replace(".", "")) Integer.parseInt Integer strB.replace(".", "") strB.replace strB "." "" long tmp = A*B_100; tmp A*B_100 A B_100 System.err.println(tmp) System.err.println System.err System System.err tmp String tmpStr = Long.toString(tmp); tmpStr Long.toString(tmp) Long.toString Long tmp int length = tmpStr.length(); length tmpStr.length() tmpStr.length tmpStr String result; result if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        } length >= 3 length 3 {
            result = tmpStr.substring(0, length-2);
        } result = tmpStr.substring(0, length-2) result tmpStr.substring(0, length-2) tmpStr.substring tmpStr 0 length-2 length 2 {
            result = "0";
        } result = "0" result "0" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long A = sc.nextLong();
        String strB = sc.next();

        int B_100 = Integer.parseInt(strB.replace(".", ""));

        long tmp = A*B_100;
        System.err.println(tmp);

        String tmpStr = Long.toString(tmp);
        int length = tmpStr.length();

        String result;
        if(length >= 3) {
            result = tmpStr.substring(0, length-2);
        }else {
            result = "0";
        }

        System.out.println(result);
    }
}