在字符串R代码中查找嵌套括号的最大深度

I have a problem to finish this R code. We are given a string having parenthesis like below “( ((X)) (((Y))) )” We need to find the maximum depth of balanced parenthesis, like 4 in above example. Since ‘Y’ is surrounded by 4 balanced parenthesis.I have a problem to finish this R code. We are