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 JavaScript (node.js v5.12) (judge verdict: Accepted)


// inputに入力データ全体が入る
function Main(input) {
  inputs = input.split(/\n/);
  // N 個の県, M個の市
  var firstLine = inputs[0]
  var firstLines = firstLine.split(/\s/)
  var n = Number(firstLines[0])
  var m = Number(firstLines[1])

  var prefs = {}
  var prefLineLength = inputs.length - 1 - 1
  for (var i = 0; i < prefLineLength; i++) {
    var prefLine = inputs[i+1]
    var prefLines = prefLine.split(/\s/)
    var p = Number(prefLines[0])
    var y = Number(prefLines[1])
    if (!prefs[p]) {
      prefs[p] = []
    }
    prefs[p].push({i: i, pref: p, year: y})
  }

  var cities = []
  for (var i = 0; i <= n; i++) {
    var pref = prefs[i]
    if (!pref) continue;
    pref.sort(function(a,b) {
      return a.year - b.year;
    })
    for (var j = 0; j < pref.length; j++) {
      pref[j].ID = ("00000"+pref[j].pref).slice(-6)+("00000"+(j+1)).slice(-6)
      cities.push(pref[j])
    }
  }

  cities.sort(function(a, b) {
    return a.i - b.i
  })

  console.log( cities.map(a => a.ID).join("\n") )
}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));