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)

'use strict'
const main = (input) => {
    input = input.split('\n')
    let temp = input[0].split(' ').map(i => parseInt(i))
    const N = temp[0]
    const M = temp[1]
    temp = input.slice(1, M + 1)
    let arr = []
    let aMap = new Map
    temp.forEach((v) => {
        let tmp = v.split(' ').map(i => parseInt(i))
        aMap.set(tmp[1], 0)
        if(arr[tmp[0]] === undefined){
            arr[tmp[0]] = []
        }
        arr[tmp[0]].push(tmp[1])
    })

    arr.forEach((v, i) => {
        v.sort((a, b) => a - b)
        v.forEach((num, j) => {
            let def = ('000000' + i.toString(10)).slice(-6) + ('000000' + (j + 1).toString(10)).slice(-6)
            aMap.set(num, def)
        })
    })
    aMap.forEach(val => console.log(val))
}

main(require('fs').readFileSync('/dev/stdin', 'utf-8'))