Sort Students By Name

You are given a list of students. Each student is represented by their first name and last name. Your task is to sort these students primarily by their last names in lexicographical order; if two or more students share the same last name, then sort them by their first name.

Input Format: The input is given through stdin. The first line contains an integer n, which represents the number of students. Each of the following n lines contains two strings: the first name and the last name of a student.

Output Format: Print the full name of each student (in the format "first_name last_name") on a separate line, following the specified sorted order.

Note: If no students are given (i.e. n = 0), no output should be produced.

inputFormat

The first line contains an integer n (0 ≤ n ≤ 10⁵), representing the number of students. Each of the next n lines contains two space-separated strings: the first name and the last name. Each name will consist of alphabetical characters only.

outputFormat

Output n lines. Each line should contain the student's full name in the format first_name last_name, sorted by last name first, and by first name if the last names are identical.

## sample

5
John Doe
Jane Smith
Alice Doe
Bob Brown
Charlie Brown

Bob Brown
Charlie Brown
Alice Doe
John Doe
Jane Smith

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