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)

function fillZero(l,num) {
	num = String(num)
	for (var i = num.length; i < l; i++) {
		num = "0" + num
	}
	return num
}

function Main(input) {
    input = input.split("\n");
    var N = parseInt(input[0].split(" ")[0]);
    var M = parseInt(input[0].split(" ")[1]);
    C = new Array(M);
    P = new Array(0);
    for (i = 0; i < M; i++) {
        tmp = input[i + 1].split(" ");
        Csub = [parseInt(tmp[0]), parseInt(tmp[1]), i];
        C[i] = Csub;
    }
	// console.log(JSON.stringify(C))
    C.sort(function (a, b) {
        if (a[0] < b[0]) return -1;
        if (a[0] > b[0]) return 1;
        if (a[1] < b[1]) return -1;
        if (a[1] > b[1]) return 1;
        return 0;
    });
    // console.log(JSON.stringify(C))

    for (i = 0; i < M; i++) {
		var cnt 
        if (i == 0) {
            cnt = 1;
        } else if (C[i][0] != C[i - 1][0]) {
            cnt = 1;
        } else {
            cnt++;
        }
        P.push(
			[C[i][0], cnt, C[i][2]]
		);
    }
	// console.log(JSON.stringify(P))
    P.sort(function (a, b) { return a[2] - b[2] });
	// console.log(JSON.stringify(P))

	for (var i = 0; i < P.length; i++) {
		console.log(fillZero(6, P[i][0]) + fillZero(6, P[i][1]))
	}
}
function debug() {
    var input = document.getElementById("input").value;
    Main(input);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));