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)

if (!String.prototype.padStart) {
    String.prototype.padStart = function padStart(targetLength,padString) {
        targetLength = targetLength>>0; //truncate if number or convert non-number to 0;
        padString = String((typeof padString !== 'undefined' ? padString : ' '));
        if (this.length > targetLength) {
            return String(this);
        }
        else {
            targetLength = targetLength-this.length;
            if (targetLength > padString.length) {
                padString += padString.repeat(targetLength/padString.length); //append to original to ensure we are longer than needed
            }
            return padString.slice(0,targetLength) + String(this);
        }
    };
}


function Main(input) {
  const data = input.split("\n")
  const a = data.shift().split(" ")
  const N = a[0]
    const M = a[1]
  const pref = []
  data.forEach( (d, i) => {
    if (d.length === 0) { return; }
    const x = d.split(" ")
      const I = x[0]
      const Y = x[1]
    var P = pref[I]
    if (P === undefined) {
      pref[I] = [[i,Y]]
    } else {
      P.push([i,Y])
    }
  })
  const r = [];

  pref.forEach( (p,pi) => {
    if (!Array.isArray(p)) { return;}
    p.sort( (a, b) => a[1] > b[1] ? 1 : a[1] === b[1] ? 0 : -1)
    p.forEach( (m, mi) => {
      r[m[0]] = ("" + pi).padStart(6, "0") + ("" + (mi + 1)).padStart(6, "0")
    })
  });

  console.log(r.join("\n"))


}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));