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

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  }
 
} import java.util.*; util.* java import java.math.*; math.* java public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  }
 
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  } main {
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long x = sc.nextLong(); x sc.nextLong() sc.nextLong sc long y = Long.parseLong(sc.next().replace(".","")); y Long.parseLong(sc.next().replace(".","")) Long.parseLong Long sc.next().replace(".","") sc.next().replace sc.next() sc.next sc "." "" BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100"))); big new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100"))) new BigDecimal(x).multiply new BigDecimal(x) new BigDecimal(y).divide(new BigDecimal("100")) new BigDecimal(y).divide new BigDecimal(y) new BigDecimal("100") String res = big.toString(); res big.toString() big.toString big if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    } res.contains(".") res.contains res "." {
   		res = res.substring(0, res.indexOf("."));
    } res = res.substring(0, res.indexOf(".")) res res.substring(0, res.indexOf(".")) res.substring res 0 res.indexOf(".") res.indexOf res "." 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){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  }
 
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  }
 
} Main
import java.util.*;
import java.math.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long x = sc.nextLong();
    long y = Long.parseLong(sc.next().replace(".",""));    
    BigDecimal big = new BigDecimal(x).multiply(new BigDecimal(y).divide(new BigDecimal("100")));
    String res = big.toString();
    if(res.contains(".")){
   		res = res.substring(0, res.indexOf("."));
    }
    System.out.println(res);
  }
 
}