ch0305-1551 Sumsets

描述

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

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

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

样例输入

1
2
3
4
5
6
7
8
9
10
11
12
13
145
2 
3 
5 
7 
12
5
2 
16 
64 
256 
1024
0

样例输出

1
2
312
no solution

来源

Waterloo local 2001.06.02

限制

• 时间限制：1000ms
• 内存限制：128MB