function identifiers(text, IDN) {
  const separators = '.,;:!?()[]\'"–-';
  for (let s of separators) {
    text = text.split(s).join(' ');
  }
  const slova = text.split(/\s+/);
  for (let slovo of slova) {
    if (slovo.length > 0 && ['I', 'Y', 'K', 'L', 'M', 'N'].includes(slovo[0].toUpperCase())) {
      IDN.push(slovo);
    }
  }
}
const text = `Ukraine[a] is a country in Eastern Europe. It is the second-largest country in Europe after Russia, which borders it to the east and northeast.[b] Ukraine also borders Belarus to the north; Poland and Slovakia to the west; Hungary, Romania and Moldova[c] to the southwest; and the Black Sea and the Sea of Azov to the south and southeast.[d] Kyiv is the nation's capital and largest city, followed by Kharkiv, Odesa, and Dnipro. Ukraine's official language is Ukrainian`;
const IDN = [];
identifiers(text, IDN);
console.log("Ідентифікатори змінних, які починаються з букв I, Y, K, L, M або N:");
console.log(IDN);

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