3208. Sumsets

输入格式

Several $S$, each consisting of a line containing an integer $1\le n\le 1000$ 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.

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

12
no solution