Draw a circuit with at most 3 gates that takes in 8 inputs b7, b6, b5, ..., b0 corresponding to a characters ASCII code, and outputs the same letter with the case changed. That is, if the input represents an uppercase letter, then the output will be the corresponding lowercase letter, and if the input represents a lowercase letter, then the output will be the corresponding uppercase letter. Your circuit can output anything it likes if the input is not a letter