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Deduplicate article tags

An editor pasted a comma-separated tag list with repeats. Print every tag once, preserving the order in which it first appeared, and join the cleaned tags with | .

Input

One line of 1 to 30 lowercase tags separated by commas.

Output

One line: unique tags separated by | .

Example 1

Input

sql,data,joins,data,practice

Output

sql | data | joins | practice

The second data tag is removed and all first occurrences keep their positions.

Constraints

  • Each tag has 1 to 20 lowercase letters
  • At least one tag is present

Hints

Hint 1 of 3

split(',') creates the input array.

Hint 2 of 3

includes tells you whether the result already has a tag.

Hint 3 of 3

push only unseen tags, then join the result.

Solution

Show a reference solution and explanation
 JavaScript · reference solution
const tags = readline().split(',');
const unique = [];
for (const tag of tags) {
  if (!unique.includes(tag)) unique.push(tag);
}
console.log(unique.join(' | '));

Why it works

The left-to-right scan preserves the first occurrence naturally. A Set could also deduplicate, but the explicit array loop makes the membership decision and output order easy to follow.

Lesson for this exercise: JavaScript Arrays: Creating, Indexing and Changing Lists

Your program
const tags = readline().split(',');
const unique = [];
// keep only first occurrences
console.log(unique.join(' | '));

Tests: 3 cases including the examples. Passing every test marks the exercise solved in this browser.

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