import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    }
} Main public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    } main {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    } try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        } {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        } Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) long A = sc.nextLong(); A sc.nextLong() sc.nextLong sc String B = sc.next(); B sc.next() sc.next sc String[] split = B.split("[.]"); split B.split("[.]") B.split B "[.]" long B1 = Long.parseLong(split[0]); B1 Long.parseLong(split[0]) Long.parseLong Long split[0] split 0 long B2 = Long.parseLong(split[1]); B2 Long.parseLong(split[1]) Long.parseLong Long split[1] split 1 long B3 = B1 * 100 + B2; B3 B1 * 100 + B2 B1 * 100 B1 100 B2 System.out.println((A * B3) / 100) System.out.println System.out System System.out (A * B3) / 100 (A * B3) A B3 100 String[] args args public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    }
} public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long A = sc.nextLong();
            String B = sc.next();
            String[] split = B.split("[.]");
            long B1 = Long.parseLong(split[0]);
            long B2 = Long.parseLong(split[1]);
            long B3 = B1 * 100 + B2;
            System.out.println((A * B3) / 100);
        }
    }
}
