Write a BNF grammar for a programming language identifier that

starts with an uppercase letter

then contains a digit followed by an underscore $(\text{'}\_\text{'})$

followed by any number of additional uppercase letters, lowercase letters, or digits

optionally ends with one of the characters $\text{'}$$$\text{'},\text{'}$@$\text{'},$ or $\text{'}^\text{'}$

Don't use the empty string symbol in your grammar.