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: Runtime Error)

function Main(input) {
	input = input.split("\n");
	tmp = input[0].split(" ");
	var n = parseInt(tmp[0], 10);
	var m = parseInt(tmp[0], 10);

    var id = {}
  	for(var i = 0; i <= m; i++) {
      py = input[i+1].split(" ");
      var p = py[0];
      var y = py[1];

      if (!(p in id)) {
        id[p] = {};
      }
      id[p][y] = 0;
	}
    Object.keys(id).forEach(function (key) {
        var i = 1;
        Object.keys(id[key]).sort().forEach(function (key2) {
            id[key][key2] = i;
            i++;
        });
    });
    for(var i = 0; i <= m; i++) {
      py = input[i+1].split(" ");
      var p = py[0];
      var y = py[1];
      console.log(('000000'+p).slice(-6)+('000000'+id[p][y]).slice(-6));
	}
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));