Acronym Generator

Create an acronym from the first letter of every word, in uppercase. Spaces and hyphens separate words. Remove every other punctuation mark and digit without adding a separator; an apostrophe inside a word does not start another word. Ignore empty pieces.

Implement acronym_generator(phrase).

Input

phrase: The phrase to shorten.

Output

Return the uppercase initials in their original order.

Constraints

0 ≤ phrase length ≤ 10,000. Input contains ASCII letters, digits, spaces, and punctuation; no tabs or line breaks. A phrase with no letters returns empty text.

Examples

Input:
phrase = "central-processing unit"

Expected output:
expected = "CPU"

Input:
std::string phrase = "central-processing unit";

Expected output:
std::string expected = "CPU";

Input:
string phrase = "central-processing unit";

Expected output:
string expected = "CPU";

Input:
phrase = "don't repeat yourself"

Expected output:
expected = "DRY"

Input:
std::string phrase = "don't repeat yourself";

Expected output:
std::string expected = "DRY";

Input:
string phrase = "don't repeat yourself";

Expected output:
string expected = "DRY";

References

This challenge is adapted for CodeUtility. Follow the statement and constraints above.

• Exercism: Acronym