import java.util.*;
import java.util.stream.*;
import java.math.*;
class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal A = new BigDecimal(sc.next());
    BigDecimal B = new BigDecimal(sc.next());
    System.out.println(A.multiply(B).setScale(0, RoundingMode.DOWN));
  }
}

/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