import java.math.BigDecimal;
import java.util.Scanner;


public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    } main {
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BigDecimal A = sc.nextBigDecimal(); A sc.nextBigDecimal() sc.nextBigDecimal sc double B = sc.nextDouble(); B sc.nextDouble() sc.nextDouble sc BigDecimal ans = A.multiply(BigDecimal.valueOf(B)); ans A.multiply(BigDecimal.valueOf(B)) A.multiply A BigDecimal.valueOf(B) BigDecimal.valueOf BigDecimal B System.out.println(ans.longValue()) System.out.println System.out System System.out ans.longValue() ans.longValue ans String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    }
} Main
import java.math.BigDecimal;
import java.util.Scanner;


public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        BigDecimal A = sc.nextBigDecimal();
        double B = sc.nextDouble();

        BigDecimal ans = A.multiply(BigDecimal.valueOf(B));
        System.out.println(ans.longValue());
    }
}
