import java.math.BigDecimal;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

public class Main {

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		BigDecimal n = sc.nextBigDecimal();
		BigDecimal m = sc.nextBigDecimal();
		
		System.out.println(n.multiply(m).setScale(0, BigDecimal.ROUND_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