Even Sum Minus Odd Sum

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Given n signed integers, compute the sum of even values minus the sum of odd values, retaining signs. Empty sums are zero.

Input

n then exactly n integers.

Output

One 64-bit integer even_sum - odd_sum.

Subtasks

• Subtask 1 (20%): n ≤ 20; |a_i| ≤ 100.

• Subtask 2 (30%): n ≤ 1000; |a_i| ≤ 10^6.

• Subtask 3 (50%): n ≤ 100000; |a_i| ≤ 10^9.

Examples

Example 1

Input:

5
-2 -3 0 4 5

Output:

0

Explanation: Even values total two and odd values total two; their difference is zero.

Example 2

Input:

0

Output:

0

Explanation: Both sums are empty and therefore zero.