import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    }
} Main public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    } main {
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc double B = sc.nextDouble(); B sc.nextDouble() sc.nextDouble sc long b = (long)((B*100.0)+0.5); b (long)((B*100.0)+0.5) (B*100.0) B 100.0 0.5 final long ans = A*b; ans A*b A b String ansstr = String.valueOf(ans); ansstr String.valueOf(ans) String.valueOf String ans if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        } ansstr.length() <= 2 ansstr.length() ansstr.length ansstr 2 {
            System.out.println("0");
        } System.out.println("0") System.out.println System.out System System.out "0" {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        } System.out.println(ansstr.substring(0, ansstr.length() - 2)) System.out.println System.out System System.out ansstr.substring(0, ansstr.length() - 2) ansstr.substring ansstr 0 ansstr.length() - 2 ansstr.length() ansstr.length ansstr 2 String args[] args public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    }
} public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long A = sc.nextLong();
        double B = sc.nextDouble();
        long b = (long)((B*100.0)+0.5);
        final long ans = A*b;
        String ansstr = String.valueOf(ans);
        if(ansstr.length() <= 2){
            System.out.println("0");
        }else {
            System.out.println(ansstr.substring(0, ansstr.length() - 2));
        }
    }
}
