import java.util.*;

public class Main{
    public static void main(String[] args)
    {
       

        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        double b=sc.nextDouble();
      long ans=(long)(a*(b*100))/100;
      System.out.println(ans);

    }
}

/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