Heaps — Eolymp

Input

The first line contains an integer $n$ ( $2 \leq n \leq 1000$ 2 \leq n \leq 1000) — the length of the sequence.

The second line contains $n$ integers separated by spaces. These numbers are given as $a_{1}, a_{2}, \dots, a_{n}$ a_1, a_2, \ldots, a_n ( $- 1 0^{6} \leq a_{i} \leq 1 0^{6}$ -10^6 \leq a_i \leq 10^6).

Output

Print the largest integer that can be obtained as the sum of two different elements.

Examples

Input: "' 5 1 2 3 4 5 "'

Output: "' 9 "'

Example 1

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Note

In the example above, the largest sum is $4 + 5 = 9$ 4 + 5 = 9.