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Odd sum

题面翻译

题目描述：

现给予你一个长度为n,包含正整数的序列 a1,a2……an，你的任务是找到一个和为奇数且值最大（在和为奇数的子序列中）的子序列。可以保证该序列中有和为奇数的子序列 子序列是一个可以通过删除一个序列中的部分元素，但不改变其他元素的顺序后得到的新序列 现在请你写一个程序找到上述的这样一个子序列

输入格式：

第一行包含一个整数***(1<=n<=10^5)*** 第二行包含n个整数a1,a2……an(-10^4<=ai<=10^4) 该序列包含至少一个和为奇数的子序列

输出格式：

输出找到的子序列的和

说明：

第一个样例中的第二个元素与第四个元素的和为3

题目描述

You are given sequence $a_{1},a_{2},...,a_{n}$ of integer numbers of length $n$ . Your task is to find such subsequence that its sum is odd and maximum among all such subsequences. It's guaranteed that given sequence contains subsequence with odd sum.

Subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements.

You should write a program which finds sum of the best subsequence.

输入格式

The first line contains integer number $n$ ( $1<=n<=10^{5}$ ).

The second line contains $n$ integer numbers $a_{1},a_{2},...,a_{n}$ ( $-10^{4}<=a_{i}<=10^{4}$ ). The sequence contains at least one subsequence with odd sum.

输出格式

Print sum of resulting subseqeuence.

样例 #1

样例输入 #1

4
-2 2 -3 1

样例输出 #1

3

样例 #2

样例输入 #2

3
2 -5 -3

样例输出 #2

-1

提示

In the first example sum of the second and the fourth elements is $3$ .