import java.io.*;
import java.util.*;
public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	}
} Main public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	} main {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	} BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); reader new BufferedReader(new InputStreamReader(System.in)) String[] lo= reader.readLine().split(" "); lo reader.readLine().split(" ") reader.readLine().split reader.readLine() reader.readLine reader " " long a = Long.parseLong(lo[0]); a Long.parseLong(lo[0]) Long.parseLong Long lo[0] lo 0 char[] pol = lo[1].toCharArray(); pol lo[1].toCharArray() lo[1].toCharArray lo[1] lo 1 String h = ""; h "" for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		} int i =0; int i =0; i 0 i<pol.length i pol.length pol pol.length i++ i++ i {
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		} {
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		} if(pol[i]=='.') continue;
			else h = h + pol[i]; pol[i]=='.' pol[i] pol i '.' continue; h = h + pol[i] h h + pol[i] h pol[i] pol i long pow =Long.parseLong(h); pow Long.parseLong(h) Long.parseLong Long h long res = (pow*a)/100; res (pow*a)/100 (pow*a) pow a 100 System.out.println(res) System.out.println System.out System System.out res String[] args args public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	}
} public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	}
} Main
import java.io.*;
import java.util.*;
public class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String[] lo= reader.readLine().split(" ");
		long a = Long.parseLong(lo[0]);
		char[] pol = lo[1].toCharArray();
		String h = "";
		for(int i =0;i<pol.length;i++){
			if(pol[i]=='.') continue;
			else h = h + pol[i];
		}
		long pow =Long.parseLong(h);
		long res = (pow*a)/100;
		System.out.println(res);
	}
}
