import java.util.*;
import java.math.*;

public class Main {
    public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
        String a = sc.next();
        String b = sc.next();
      
        BigDecimal a1 = new BigDecimal(a);
        BigDecimal b1 = new BigDecimal(b);
        BigDecimal res= a1.multiply(b1);
      
        System.out.println(res.setScale(0, RoundingMode.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