Evaluate Mathematical Expression

Given a string representing a mathematical expression, your task is to evaluate it correctly. The expression may contain non-negative integers, decimal numbers, operators +, -, *, /, and parentheses ( ). The evaluation must follow the standard operator precedence rules, i.e. $$\text{PEMDAS}$$ (or BODMAS).

For example, the expression 3 + 5 * 2 / (7 - 3) evaluates to 5.5. Note that spaces can appear arbitrarily in the input expression.

inputFormat

The input consists of a single line read from standard input (stdin), which is the expression to evaluate.

Example:

2 + 3 * (4 - 1)

outputFormat

Output a single number to standard output (stdout) representing the evaluated result of the expression. If the result is mathematically an integer, you may output it without any decimal point; otherwise, include the fractional part.

2 + 3

5