import java.util.*;
import java.math.BigDecimal;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    BigDecimal aActual = new BigDecimal(sc.next());
    BigDecimal bActual = new BigDecimal(sc.next());
    BigDecimal ansActual = aActual.multiply(bActual);
    BigDecimal ans = ansActual.setScale(0, BigDecimal.ROUND_DOWN);
    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