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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)


import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws Exception {

//		System.setIn(new FileInputStream("D:\\Workspace\\SW\\src\\b\\tt"));
//		long start = System.currentTimeMillis();

		// strat
		// B - ID
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		StringTokenizer st = new StringTokenizer(br.readLine());
		int N = Integer.parseInt(st.nextToken());
		int M = Integer.parseInt(st.nextToken());

		int[] P = new int[N + 1];
		int[][] arr = new int[M + 1][4];// 0 保存原值P，1保存原值Y， 2排序， 3州内顺序

		for (int i = 1; i <= M; i++) {
			st = new StringTokenizer(br.readLine());
			int p = Integer.parseInt(st.nextToken());
			int y = Integer.parseInt(st.nextToken());

			arr[i][0] = p;
			arr[i][1] = y;
			arr[i][2] = i;
		}

		Comparator<int[]> c = new Comparator<int[]>() {
			@Override
			public int compare(int[] o1, int[] o2) {
				return o1[1] - o2[1];
			}
		};
		Arrays.sort(arr, c);

		for (int i = 1; i <= M; i++) {
			arr[i][3] = ++P[arr[i][0]];
		}

		Comparator<int[]> c1 = new Comparator<int[]>() {
			@Override
			public int compare(int[] o1, int[] o2) {
				return o1[2] - o2[2];
			}
		};
		Arrays.sort(arr, c1);

		for (int i = 1; i <= M; i++) {
			System.out.format("%06d%06d\n", arr[i][0], arr[i][3]);
		}

		// end
//		long end = System.currentTimeMillis();
//		System.out.format("%.3f (s)", (end-start)/1000.0);
	}

}