import java.util.*;
import java.math.BigDecimal;
public class Main {
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    BigDecimal A = sc.nextBigDecimal();
		BigDecimal B = sc.nextBigDecimal();		
		BigDecimal ans = A.multiply(B);
		System.out.println(ans.toBigInteger());
  }
}  
/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