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)

var lines = [];

var readline = require("readline");

var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});

rl.on('line', function (x) {
    lines.push(x);
});

rl.on('close', function () {
    var tmp = lines.shift();
    var n = Number(tmp.split(" ")[0]);
    var m = Number(tmp.split(" ")[1]);

    var city = Array(m);
    var result = "";

    for (var i = 0; i < m; i++) {
        tmp = lines[i].split(" ");
        city[i] = {
            "i": i,
            "P": Number(tmp[0]),
            "Y": Number(tmp[1]),
            "KenNum": "",
            "ShiNum": "",
        }
    }

    city.sort(function (a, b) {
        if (a.P < b.P) return -1;
        if (a.P > b.P) return 1;
        if (a.Y < b.Y) return -1;
        if (a.Y > b.Y) return 1;
        return 0;
    });

    var ken  = 1;
    var shi  = 1;
    var loop = 0;
    
    for (var i=0;i<m;i++) {
        if(ken === city[i].P) {
            city[i].KenNum = ken.toString();
            loop = 6 - ken.toString().length;

            for (var k = 0; k < loop; k++) { city[i].KenNum = "0" + city[i].KenNum; }

            city[i].ShiNum = shi.toString();
            loop = 6 - shi.toString().length;

            for (var k = 0; k < loop; k++) { city[i].ShiNum = "0" + city[i].ShiNum; }
            shi++;
        }
        else{ken++; shi=1; i--;}
    }
    city.sort(function(a,b){return(a.i-b.i)});
    for (var i=0;i<m;i++) {
        console.log(city[i].KenNum+city[i].ShiNum);
    }
});