Consider the following description of a simple programming language for evaluating arithmetic expressions: An operator is one of the characters + - */ A number is any sequence of one or more of the digits 0-9 (example: 42) A list expression is defined as an open parenthesis"(", followed by an operator, followed by a space, followed by one or more expressions (each separated by spaces) and terminated by a close parenthesis). An expression is defined as either a number or a list expression. A single list expression defines a valid program. An example might look like either of the following: (+ (* 5 3) (/ 8 4)) (- 25 (+ 4 2)) Is this language regular? Why or why not? If the language is regular, provide a regular expression for valid programs