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.

Restrições

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.

Exemplos

Entrada:
phrase = "central-processing unit"

Saída esperada:
expected = "CPU"

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

Saída esperada:
std::string expected = "CPU";

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

Saída esperada:
string expected = "CPU";

Entrada:
phrase = "don't repeat yourself"

Saída esperada:
expected = "DRY"

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

Saída esperada:
std::string expected = "DRY";

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

Saída esperada:
string expected = "DRY";

Referências

Este desafio foi adaptado para o CodeUtility. Siga o enunciado e as restrições acima.

• Exercism: Acronym