C*++ language is quite similar to C++. The similarity manifests itself in the fact that the programs written in C*++ sometimes behave unpredictably and lead to absolutely unexpected effects. For example, let's imagine an arithmetic expression in C*++ that looks like this (expression is the main term):

• expression ::= summand | expression + summand | expression - summand
• summand ::= increment | coefficient*increment
• increment ::= a++ | ++a
• coefficient ::= 0|1|2|...|1000

For example, "5*a++-3*++a+a++" is a valid expression in C*++.

Thus, we have a sum consisting of several summands divided by signs "+" or "-". Every summand is an expression "a++" or "++a" multiplied by some integer coefficient. If the coefficient is omitted, it is suggested being equal to 1.

The calculation of such sum in C*++ goes the following way. First all the summands are calculated one after another, then they are summed by the usual arithmetic rules. If the summand contains "a++", then during the calculation first the value of the "a" variable is multiplied by the coefficient, then value of "a" is increased by 1. If the summand contains "++a", then the actions on it are performed in the reverse order: first "a" is increased by 1, then — multiplied by the coefficient.

The summands may be calculated in any order, that's why sometimes the result of the calculation is completely unpredictable! Your task is to find its largest possible value.

The first input line contains an integer a ( - 1000 ≤ a ≤ 1000) — the initial value of the variable "a". The next line contains an expression in C*++ language of the described type. The number of the summands in the expression does not exceed 1000. It is guaranteed that the line describing the expression contains no spaces and tabulation.

Output a single number — the maximal possible value of the expression.