Given an array of strings emails where each string represents an email address, return the number of distinct email addresses that actually receive mail after normalization.

Each email address contains a local name and a domain name separated by an '@' character.

The normalization rules are as follows:

• Local Name Rules:

  • Characters are case insensitive, so all uppercase letters are converted to lowercase.

  • Any periods '.' are ignored and removed.

  • If a plus character '+' appears, all characters following the first '+' are ignored and removed.

• Domain Name Rules:

  • Characters are case insensitive, so all uppercase letters are converted to lowercase.

  • Periods '.' are preserved.

Two email addresses are considered part of the same group if their normalized forms are identical.

Constraints:

• $1 \le$ emails.length $\le 1000$

• $1 \le$ emails[i].length $\le 100$

• emails[i] consists of lowercase and uppercase English letters, digits, and the characters '.' , '+', and '@'.

• Each emails[i] contains exactly $1$ '@' character.

• All local and domain names are non-empty; local names do not start with '+'.

• Domain names end with the ".com" suffix and contain at least $1$ character before ".com".

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