import java.io.*;
import java.math.BigDecimal;
import java.util.*;

class Main{
    public static void main(String args[])throws IOException{
        try(BufferedReader br = new BufferedReader(new InputStreamReader(System.in))){
          String[] input = br.readLine().split(" ");

          long A = Long.parseLong(input[0]);

          BigDecimal num = new  BigDecimal(input[1]);
          BigDecimal hum = new BigDecimal("100");
          BigDecimal mul = num.multiply(hum);       

          int tmp = mul.intValue();
          long result = 0;
          result = (A * tmp)/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