Evaluate Mathematical Expression

You are given a string representing a mathematical expression that consists of non-negative integers, the addition operator +, and the multiplication operator *. The expression may include arbitrary spaces. Your task is to evaluate the expression according to the standard operator precedence: multiplication is performed before addition.

Note: The expression will only contain integers, +, and *. There will be no subtraction, division, or parentheses in the expression.

The mathematical formula can be summarized as follows:

\( result = \sum_{i=1}^{n} \prod_{j=1}^{m_i} a_{ij} \)

where each aij is a non-negative integer.

inputFormat

The input consists of a single line that contains the expression as a string. The expression may include spaces.

Example: 3 + 2 * 2

outputFormat

Output a single integer which is the result of evaluating the expression.

3 + 2 * 2

7