Arithmetic Expression Evaluator

You are given a mathematical expression as a string. The expression consists of non-negative integers, the four basic arithmetic operations +, -, *, /, and parentheses ( ). Your task is to evaluate the expression following the standard operator precedence and using integer division for the '/' operator (i.e. flooring the result).

The evaluation should respect the following rules:

• Parentheses have the highest precedence.
• The multiplication and division operators have higher precedence than addition and subtraction.
• When operators have the same precedence, evaluate them from left to right.

For example, the expression 3 + 2 * 2 evaluates to 7 and 10 + (2 * 3) evaluates to 16.

Your program should read the input expression from standard input and write the result to standard output.

inputFormat

The input consists of a single line containing the arithmetic expression.

The expression includes non-negative integers, spaces, the operators +, -, *, / and parentheses ( and ). You can assume the expression is valid.

outputFormat

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

3 + 2 * 2

7