import java.util.*;
import java.io.*;
import java.math.*;

public class Main{
  public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  }
} import java.util.*; util.* java import java.io.*; io.* java import java.math.*; math.* java public class Main{
  public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  }
} Main public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  } main {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String[] S = sc.nextLine().split(" "); S sc.nextLine().split(" ") sc.nextLine().split sc.nextLine() sc.nextLine sc " " BigDecimal A = new BigDecimal(S[0]); A new BigDecimal(S[0]) BigDecimal B = new BigDecimal(S[1]); B new BigDecimal(S[1]) System.out.println(A.multiply(B).longValue()) System.out.println System.out System System.out A.multiply(B).longValue() A.multiply(B).longValue A.multiply(B) A.multiply A B String[] args args public class Main{
  public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  }
} public class Main{
  public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  }
} Main
import java.util.*;
import java.io.*;
import java.math.*;

public class Main{
  public static void main(String[] args)throws Exception{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    Scanner sc = new Scanner(System.in);
    String[] S = sc.nextLine().split(" ");
    BigDecimal A = new BigDecimal(S[0]);
    BigDecimal B = new BigDecimal(S[1]);
    System.out.println(A.multiply(B).longValue());
  }
}
