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 Scala (2.11.7) (judge verdict: Time Limit Exceeded)


object Main extends App {

  import scala.io.StdIn._

  val Array(n, m) = readLine.trim.split(' ').map(_.toInt)
  val pref = Array.tabulate(n){ _ ⇒ 0}
  val town = Array.tabulate(m){_ ⇒
    val Array(p, y) = readLine.trim.split(' ').map(_.toInt)
    Town(p, y)
  }.zipWithIndex.sortBy(_._1.year)

  val id = Array.tabulate(m){_ ⇒ ""}
  for ((Town(p, y), i) ← town) {
    pref(p - 1) += 1
    id(i) = ("0" * 6 + p.toString).takeRight(6) + ("0" * 6 + pref(p - 1).toString).takeRight(6)
  }
  for (name ← id){
    println(name)
  }

  case class Town(pref: Int, year:Int)
  implicit class ScopeFunc[T](val value: T) {
    def let[A](func: T ⇒ A): A = func(value)
    def also(func: T ⇒ Unit): T = {
      func(value)
      value
    }
  }
}

/*
 */