import java.util.*;
import java.io.*;
 
class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    double m = sc.nextLong();
    long result = (long)Math.round(m*100);
    
    result = result*n/100;
    
    System.out.println(result);
  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz