~~his friend~~ [REDACTED]! He has individual candies, which he organized in order to eat 1 for the next days such that each day has a specific associated candy. Each candy has a sweetness value of , and ~~because [REDACTED] is sweet~~ wishes to maximize the sweetness he eats over the days. However, if eats a 2 candies in a row with a sum greater than , he will spontaneously combust. Thus, sometimes must skip eating candies on certain days in order to live. Please help !

#### Input Specification

The first line will contain .

The next line will contain integers .

#### Output Specification

The maximum sweetness that

can eat from the candies.#### Subtasks

##### Subtask 1 [30%]

##### Subtask 2 [70%]

No further constraints.

#### Sample Input

```
5 5
5 1 2 3 4
```

#### Sample Output

`6`

#### Sample Explanation

Alan eats the second, third, and fourth candies.

## Comments