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: Time Limit Exceeded)

#include <stdio.h>
#include <math.h>
#define MAXSIZE 100000

void bubblesort(int a[MAXSIZE], int n);

int get_digit(int x);

int main(void){
    int n, m;
    scanf("%d %d", &n, &m);
    int p[MAXSIZE], y[MAXSIZE];
    int p_min = MAXSIZE + 1, p_max = -1;
    for(int i = 0; i < m; i++){
        scanf("%d %d", &p[i], &y[i]);
        if(p[i] < p_min) p_min = p[i];
        if(p[i] > p_max) p_max = p[i];
    }

    int upper[MAXSIZE], lower[MAXSIZE];
    for(int i = p_min; i <= p_max; i++){
        int y_list_to_sort[MAXSIZE];
        int y_list_num = 0;
        for(int j = 0; j < m; j++){
            if(p[j] == i){
                upper[j] = i;
                y_list_to_sort[y_list_num] = y[j];
                y_list_num++;
            }
        }
        bubblesort(y_list_to_sort, y_list_num);
        for(int j = 0; j < m; j++){
            if(p[j] == i){
                for(int k = 0; k < y_list_num; k++){
                    if(y_list_to_sort[k] == y[j]){
                        lower[j] = k + 1;
                        break;
                    }
                }
            }
        }
    }
    for(int i = 0; i < m; i++){
        for(int j = 0; j < 6 - get_digit(upper[i]); j++){
            printf("0");
        }
        printf("%d", upper[i]);
        for(int j = 0; j < 6 - get_digit(lower[i]); j++){
            printf("0");
        }
        printf("%d\n", lower[i]);
    }
    return 0;
}

void bubblesort(int a[MAXSIZE], int n){
    int escape = 0;
    while(!escape){
        escape = 1;
        for(int i = 0; i < n - 1; i++){
            if(a[i] > a[i + 1]){
                int tmp = a[i];
                a[i] = a[i + 1];
                a[i + 1] = tmp;
                escape = 0;
            }
        }
    }
    return;
}

int get_digit(int x){
    int digit = 0;
    while(x > 0){
        x /= 10;
        digit++;
    }
    return digit;
}