#### Backstory

Enming has been bullying soupy boy by using his height advantage, always patting his head and calling him small, now soupy boy, who wields the power of creating the problems for Enming's quiz, uses it to get revenge.

Surprisingly, Enming has been getting better at coding! Thus, soupy boy now wants to give him a challenge.

Enming Is given an array consisting of integers, he needs to find the **maximum** value of the following expression:

where and are the array elements.

#### Input Specification

First line contains the integer the number of elements in the array.

Second line contains space separated integers .

#### Output Specification

Print the maximum value of the above given expression.

#### Constraints

#### Sample Input 1

```
3
1 1 1
```

#### Sample Output 1

`2`

#### Explanation Of Sample 1

If we choose and , then we get the maximum value of .

#### Sample Input 2

```
4
1 2 3 1
```

#### Sample Output 2

`4`

#### Explanation Of Sample 2

If we choose and , then we get the maximum value of .

## Comments