Question

the strong room of ABC bank there are N vaults arranged in a circle. The amount of money inside each vault displayed on the door. You can empty any number of vaults as long as you do not empty more than 2 out of any 5 adjacent vaults. If you attempt to break more than 2 of any 5 adjacent vaults, an alarm sounds and the sentry a sharp shooter will kill you instantly with his laser gun! Note that as the vaults are arranged in a circle, the last vault is adjacent to the first one.

The output is the maximum amount of money that can be emptied without sounding the alarm

Input Format:

The first line contains an integer N which is the number of vaults. The next line has a sequence of positive integers of length N, giving the amount of cash in its vaults in order

Output Format:

The maximum amount of money that can be looted without sounding the alarm.

Constraints:

N<=50, Amount in each vault <=50000


Example 1

Input
9
1000, 2000, 1000, 5000, 9000, 5000, 3000, 4000, 1000

Output
15000

Explanation
The vaults 1, 5, 6 are looted, giving a total loot of (1000+5000+9000)=15000


Example 2

Input
10
1000,2000,3000,5000,9000,7000,6000,4000,7000,5000

Output
26000

Answer 1

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