Java - How to parse numbers and characters from this string? : <p>i have a calculator, my problem is that i want to somehow parse the int from the string and then calculate the result, i know subtraction should be first but is there any pattern to do this correctly? 
 <a href="https://i.stack.imgur.com/Ueul1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ueul1.png" alt="calc"></a></p>
