# Sumsets

Time Limit: 1000MS

Memory Limit: 65536K

## Description

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

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.

## Output

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

## Sample Input

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


## Sample Output

12
no solution


## Source

Waterloo local 2001.06.02