Unique Elements

You are given a sequence of integers. Your task is to remove all duplicate elements from the sequence, keeping only the first occurrence of each element. In other words, given an array \( a_1, a_2, \dots, a_N \), output the unique elements in the same order they first appear.

Example:

Input: 7
       1 2 2 3 4 4 5
Output: 1 2 3 4 5

inputFormat

The input is given via stdin and consists of two lines:

• The first line contains a single integer \( N \) (\( 0 \leq N \leq 10^5 \)), representing the number of elements in the sequence.
• The second line contains \( N \) integers separated by spaces, representing the elements \( a_1, a_2, \dots, a_N \).

outputFormat

Print the unique elements separated by a single space, in the order they first appear in the input. Output should be sent to stdout.

7
1 2 2 3 4 4 5

1 2 3 4 5