

import java.util.*; 
import java.math.*;
public 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());
		BigDecimal c = a.multiply(b);
		BigDecimal d = c.setScale(0,RoundingMode.FLOOR);
		System.out.println(d);
		sc.close();
	}
 
}
/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