Largest Perimeter of Triangle

You are given an array of positive integers representing the lengths of line segments. Your task is to find the largest possible perimeter of a non-degenerate triangle that can be formed by selecting any three of these segments.

A triangle is non-degenerate if it has a non-zero area. In terms of side lengths, for three sides \( a, b, c \) (where \( a \) is the largest), this is equivalent to the condition:

\( a < b + c \)

If no valid triangle can be formed, output 0.

The input is read from standard input and the result should be printed to standard output.

inputFormat

The first line contains a single integer \( n \) denoting the number of elements in the array.

The second line contains \( n \) space-separated integers representing the side lengths.

outputFormat

Output a single integer representing the largest perimeter of a non-degenerate triangle. If no valid triangle exists, output 0.

3
2 1 2

5