Evaluate Mathematical Expression

Given a mathematical expression as a string, compute its integer result. The expression contains non-negative integers and the binary operators + and -. Whitespace can appear anywhere in the expression and should be ignored during evaluation. The expression is guaranteed to be valid and may include multi-digit numbers.

For example, the expression 3 + 4 - 2 evaluates to 5, and 100 - 50 + 25 evaluates to 75.

inputFormat

The input consists of a single line containing the mathematical expression. The expression may include spaces.

outputFormat

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

3 + 4 - 2

5