Largest Triangular Number

You are given a list of positive integers representing side lengths. Your task is to determine the largest perimeter of any triangle that can be formed using three of these integers.

A triangle is valid if it satisfies the triangle inequality: \(a+b>c\), \(a+c>b\), and \(b+c>a\), where \(a\), \(b\), and \(c\) are the side lengths.

If no valid triangle can be formed, output -1.

inputFormat

The first line contains an integer n, the number of side lengths. The second line contains n space-separated positive integers representing the side lengths.

outputFormat

Output a single integer representing the largest triangle perimeter possible, or -1 if no valid triangle can be formed.

## sample

5
2 1 2 1 2

6

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