There are 2 questions: the first one was easy but the second one was hard for me.\nThe general idea of question 2 is like designing a function that receives a string containing of 2 different commands: add (for addition) and sub (for subtraction). That function should return an integer.\nFor example:\n"add(add(2,2),add(2,2))" -> 8\n"add(sub(-1,3),add(25,2))" -> 23\n"add(sub(-1,3),4)" -> 0\n"sub(1,add(1,sub(1,1)))" -> 0\n\nAny idea how to solve this problem? I\'ve been struggling with it for a day. Also, if the commands do not have the same length (i.e., multiple, addition, subtraction, division), what should I do?

There are 2 questions: the first one was easy but the second one was hard for me.\nThe general idea of question 2 is like designing a function that receives a s