Codeforces Calculating Function

题目链接：http://codeforces.com/contest/486/problem/A

题目分析：注意数据的大小

import java.util.Scanner;public class Calculating_Function {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);long n = scanner.nextLong();if(n % 2 == 0) {System.out.println(n / 2);} else {System.out.println(-(Math.abs(n)+1)/2);}}}