Vanya and Brackets
题意翻译
Vanya正在认真地做他的数学作业，他碰到了一个长度为N的序列，构成序列的元素都在1~9之间，并且各个元素由加号和等号构成了一个式子。
Vanya现在需要通过增加一组小括号来改变运算顺序（运算优先级，括号>乘法>加法）。
**输入格式：**
一个不带括号的式子。
**输出格式：**
加了一组小括号后该式子能达到的最大值。
**说明：**
其中式子元素个数小于等于5001。
题目描述
Vanya is doing his maths homework. He has an expression of form , where $ x_{1},x_{2},...,x_{n} $ are digits from $ 1 $ to $ 9 $ , and sign  represents either a plus '+' or the multiplication sign '\*'. Vanya needs to add one pair of brackets in this expression so that to maximize the value of the resulting expression.
输入输出格式
输入格式
The first line contains expression $ s $ ( $ 1<=|s|<=5001 $ , $ |s| $ is odd), its odd positions only contain digits from $ 1 $ to $ 9 $ , and even positions only contain signs $ + $ and $ * $ .
The number of signs $ * $ doesn't exceed 15.
输出格式
In the first line print the maximum possible value of an expression.
输入输出样例
输入样例 #1
3+5*7+8*4
输出样例 #1
303
输入样例 #2
2+3*5
输出样例 #2
25
输入样例 #3
3*4*5
输出样例 #3
60
说明
Note to the first sample test. $ 3+5*(7+8)*4=303 $ .
Note to the second sample test. $ (2+3)*5=25 $ .
Note to the third sample test. $ (3*4)*5=60 $ (also many other variants are valid, for instance, $ (3)*4*5=60 $ ).