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.
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
Output for Sample Input
12
no solution