import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;
// A - Multiplication 1
class Main{
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		BigDecimal A = sc.nextBigDecimal();

		BigDecimal B = sc.nextBigDecimal();

		BigDecimal w = A.multiply(B);

		BigDecimal ans = w.setScale(0, RoundingMode.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