Closest to 21

Difficulty: 1000 2000 ms 128 MB

implementation

Pick exactly TWO cards whose total is as large as possible without exceeding 21. Print that total, or −1 if every pair busts.

Input: the first line has N; the second line has the N card values.

Output: the best pair total ≤ 21, or −1.

Constraints:

• 2 ≤ N ≤ 500
• 1 ≤ card ≤ 11

Sample Tests

4
10 11 5 6

21

2
11 11

-1

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