Get Final String

Repeatedly delete the contiguous substring AWS from the string until no more deletions are possible, and output the remaining string; output -1 if it is empty.

输入格式

One line containing a string of uppercase English letters, 1≤length≤100000.

输出格式

Output the final string; output -1 if it is empty.

样例 1

输入：

AWAWSSG

输出：

G

样例 2

输入：

AWS

输出：

-1

样例 3

输入：

XYZ

输出：

XYZ

样例说明

The examples give G, -1 and XYZ respectively.