import java.util.*;
import java.io.*;
public class Main{
   public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   }
} import java.util.*; util.* java import java.io.*; io.* java public class Main{
   public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   }
} Main public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   } main {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st = new StringTokenizer(br.readLine()); st new StringTokenizer(br.readLine()) PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) long n = Long.parseLong(st.nextToken()); n Long.parseLong(st.nextToken()) Long.parseLong Long st.nextToken() st.nextToken st double m = Double.parseDouble(st.nextToken()); m Double.parseDouble(st.nextToken()) Double.parseDouble Double st.nextToken() st.nextToken st long res = Math.round(m*100); res Math.round(m*100) Math.round Math m*100 m 100 long ans = res*n; ans res*n res n out.println(ans/100) out.println out ans/100 ans 100 out.close() out.close out String[] main main public class Main{
   public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   }
} public class Main{
   public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   }
} Main
import java.util.*;
import java.io.*;
public class Main{
   public static void main(String[] main) throws Exception{
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      PrintWriter out = new PrintWriter(System.out);
      long n = Long.parseLong(st.nextToken());
      double m = Double.parseDouble(st.nextToken());
      long res = Math.round(m*100);
      long ans = res*n;
      out.println(ans/100);
      out.close();
   }
}
