Problem:
Score: 300 points

Problem Statement

In Republic of Atcoder, there are N prefectures, and a total of M cities that belong to those prefectures.

City i is established in year Y_i and belongs to Prefecture P_i.

You can assume that there are no multiple cities that are established in the same year.

It is decided to allocate a 12-digit ID number to each city.

If City i is the x-th established city among the cities that belong to Prefecture i, the first six digits of the ID number of City i is P_i, and the last six digits of the ID number is x.

Here, if P_i or x (or both) has less than six digits, zeros are added to the left until it has six digits.

Find the ID numbers for all the cities.

Note that there can be a prefecture with no cities.

Constraints

1 \leq N \leq 10^5

1 \leq M \leq 10^5

1 \leq P_i \leq N

1 \leq Y_i \leq 10^9

Y_i are all different.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
P_1 Y_1
:
P_M Y_M

Output

Print the ID numbers for all the cities, in ascending order of indices (City 1, City 2, ...).

Sample Input 1

2 3
1 32
2 63
1 12

Sample Output 1

000001000002
000002000001
000001000001

As City 1 is the second established city among the cities that belong to Prefecture 1, its ID number is 000001000002.

As City 2 is the first established city among the cities that belong to Prefecture 2, its ID number is 000002000001.

As City 3 is the first established city among the cities that belong to Prefecture 1, its ID number is 000001000001.

Sample Input 2

2 3
2 55
2 77
2 99

Sample Output 2

000002000001
000002000002
000002000003

Solution in Common Lisp (SBCL 1.1.14) (judge verdict: Runtime Error)

(defvar *N* (read))
(defvar *M* (read))

(defun shape-ans (n lst)
  (let ((tmp-lst (list nil)))
    (dolist (x lst)
      (when (= n (car x))
        (push (cdr x) tmp-lst)))
    (setq tmp-lst (sort (cdr (reverse tmp-lst)) #'<))
    (let ((count 0)
          (tmp-alist (list nil))
          (r-lst (list nil))
          (flag nil))
      (dolist (x tmp-lst)
        (push (cons x (incf count)) tmp-alist))
      (setq tmp-alist (cdr (reverse tmp-alist)))
      (dolist (x lst)
        (dolist (y tmp-alist)
          (when (eql (cdr x) (car y))
                (push (cons 0 (concatenate 'string (format nil "~6,'0D" n) (format nil "~6,'0D" (cdr y)))) r-lst)
                (setq flag t)))
        (unless flag
          (push x r-lst))
        (setq flag nil))
      (cdr (reverse r-lst)))))

(defun main ()
  (let ((lst (list nil)))
    (dotimes (x *M*)
      (let ((a (read))
            (b (read)))
        (push (cons a b lst))))
    (setq lst (cdr (reverse lst)))
    (dotimes (x *N*)
      (setq lst (shape-ans (1+ x) lst)))
    (dolist (result lst)
      (when (= 0 (car result))
        (princ (cdr result))))))

(main)