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: Wrong Answer)

"use strict"
 
function Main(input) {
  let args = input.split("\n");
 
  let NM = args[0].split(" ");
 
  let N = parseInt(NM[0], 10);
  let M = parseInt(NM[1], 10);
 
  args.shift();
 
  let citys = args.map((e, i) => {
    let cityInfo = e.split(" ").map(e => parseInt(e));
    return [i, cityInfo[0], cityInfo[1]]
  });
 
  citys.sort((a, b) => (a[2] - b[2]));
 
  let countryCount = Array(N + 1).fill(1);
 
  citys.forEach((e) => {
    e[3] = ('000000' + e[1]).slice(-6) + ('000000' + countryCount[e[1]]).slice(-6);
    countryCount[e[1]]++;
  });
 
  citys.sort((a, b) => (a[0] - b[0]));
 
  let result = '';
  citys.forEach(e => result += (e[3] + '\n'));
  console.log(result.trim());
}
 
//*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"));