题目描述

Problem C - Sumsets

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.

输入格式

Several S, each consisting of a line containing an integer 1 <= n <= 1000 indicating the number of elements in S, followed by the elements of S, one per line. Each element of S is a distinct integer between -536870912 and +536870911 inclusive. The last line of input contains 0.

输出格式

For each S, a single line containing d, or a single line containing "no solution".

样例 1

输入

5
2 
3 
5 
7 
12
5
2 
16 
64 
256 
1024
0

输出

12
no solution

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题目来源：fps-zhblue-waterloo-010602.xml；FPS 共享题包，题包内第 3 题。保留原作者与原赛事署名。