Given $S$, a set of integers, find the largest $d$ such that $a + b + c = d$ where $a, b, c$ and $d$ are distinct elements of $S$.

-----Input-----
The input starts with an integer $1 \le N \le 4000$, the number of elements in $S$. It is followed by $N$ lines containing the elements of $s$, one per line. Each element of $S$ is a distinct integer between $-536870912$ and $+536870911$, inclusive.

-----Output-----
Output a single line containing the maximum $d$ as described in the statement. If no such $d$ exists, output a single line containing no solution.

-----Examples-----
Sample Input:
5
2
3
5
7
12
Sample Output:
12

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