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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct city {
	int P;
	int Y;
	int cityNo;
	long long int autheNo;
};

int ascY(const void *a, const void *b) {
	struct city *A = (struct city *)a;
	struct city *B = (struct city *)b;
	return A->Y - B->Y;
}

int ascCityNo(const void *a, const void *b) {
	struct city *A = (struct city *)a;
	struct city *B = (struct city *)b;
	return A->cityNo - B->cityNo;
}

int main() {
	int N, M, i, Pcount[100000];
	struct city ans[100000];
	memset(Pcount, 0, sizeof(Pcount));

	scanf("%d %d", &N, &M);
	for (i = 0; i < M; i++) {
		scanf("%d %d", &ans[i].P, &ans[i].Y);
		ans[i].cityNo = i + 1;
	}

	qsort(ans, M, sizeof(struct city), ascY);

	for (i = 0; i < M; i++) {
		++Pcount[ans[i].P];
		ans[i].autheNo = ans[i].P * 1000000 + Pcount[ans[i].P];
	}

	qsort(ans, M, sizeof(struct city), ascCityNo);

	for (i = 0; i < M; i++) {
		printf("%012d\n", ans[i].autheNo);
	}

	return 0;
}