The developers are working on optimising the capacity of their cloud system. In the system, there are n servers where the memory capacity of the i-th server is represented by the array memory[i].

A system always contains an even number of servers.
If the system has 2x servers, then x of them will be primary and the other x will be backup servers.

For each primary server P, there exists a backup server B where the memory capacity of B ≥ memory capacity of P. The system's memory capacity is the sum of the memory capacity of all the primary servers.

Given n servers and an array memory, find the maximum system memory capacity that can be formed using the n servers.

Example
Given 5 servers as [serverA, serverB, serverC, serverD, serverE] having memory = [2, 4, 3, 1, 2].

Primary Servers Options	Backup Servers Options	Conditions	Valid Option
serverA, serverB	serverC, serverD	memory[serverA] ≤ memory[serverC], memory[serverB] ≤ memory[serverD]	No
serverA, serverD	serverB, serverE	memory[serverA] ≤ memory[serverB], memory[serverD] ≤ memory[serverE]	Yes
serverA, serverC	serverE, serverB	memory[serverA] ≤ memory[serverE], memory[serverC] ≤ memory[serverB]	Yes

In the second configuration, the system memory capacity is memory[serverA] + memory[serverD] = 3.
While in the third configuration, it is memory[serverA] + memory[serverC] = 5.
Hence, the maximum system memory capacity is 5.

Function Description
Complete the function maximumCapacity in the editor below.
maximumCapacity has the following parameter:

• int memory[n]: the memory capacity of the given servers
Returns
• long int: the maximum system memory capacity

Constraints
2 ≤ n ≤ 2*10^5
1 ≤ size[i] ≤ 10^9

Sample Case 0:

Input:
4
1 2 1 2

Output:
3

Explanation:
Here, we have 4 servers [serverA, serverB, serverC, serverD] having memory sizes as [1, 2, 1, 2].

We can choose serverA and serverB as primary servers, and serverC and serverD as their respective backup.
The conditions hold true since memory[serverC] ≥ memory[serverA] and memory[serverD] ≥ memory[serverB].
Hence, the maximum system memory capacity is 3.

Sample Case 1:

Input:
3
1 2 1

Output:
1

Explanation:
Here, we have 3 servers [serverA, serverB, serverC] having memory sizes as [1, 2, 1].

We can choose serverA as a primary server, and serverB as its respective backup server.
The conditions hold true since memory[serverB] ≥ memory[serverA].
Hence, the maximum system memory capacity is 1.