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: Runtime Error)

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

typedef char                SINT8;
typedef unsigned char       UINT8;
typedef short               SINT16;
typedef unsigned short      UINT16;
typedef int                 SINT32;
typedef unsigned int        UINT32;
typedef long long           SINT64;
typedef unsigned long long  UINT64;

#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define ABS(a) ((a)>(0)?(a):-(a))


void quick_sort (int array[],int sub_array1[],int sub_array2[], int left, int right);
void swap_int (int *x,  int *y);
int partition (int array[],int sub_array1[],int sub_array2[], int left, int right);



void swap_int (int *x,  int *y) {
    int temp;
    temp = *x;
    *x = *y;
    *y = temp;
}
 
int partition (int array[],int sub_array1[],int sub_array2[], int left, int right) {
    int i, j, pivot;
    i = left;
    j = right + 1;
    pivot = left;   // 先頭要素をpivotとする
 
    do {
        do { i++; } while (array[i] < array[pivot]);
        do { j--; } while (array[pivot] < array[j]);
        // pivotより小さいものを左へ、大きいものを右へ
        if (i < j) {
            swap_int(&array[i], &array[j]);
            swap_int(&sub_array1[i], &sub_array1[j]);
            swap_int(&sub_array2[i], &sub_array2[j]);
        }
    } while (i < j);
 
    swap_int(&array[pivot], &array[j]);   //pivotを更新
    swap_int(&sub_array1[pivot], &sub_array1[j]);   //pivotを更新
    swap_int(&sub_array2[pivot], &sub_array2[j]);   //pivotを更新
    return j;
}
 

void quick_sort (int array[],int sub_array1[],int sub_array2[], int left, int right) {
    int pivot;
    if (left < right) {
        pivot = partition(array,sub_array1,sub_array2, left, right);
        // pivotを境に再帰的にクイックソート
        quick_sort(array,sub_array1,sub_array2, left, pivot-1);
        quick_sort(array,sub_array1,sub_array2, pivot+1, right);
    }
}


SINT32 main() {
    SINT32 n,m;
    scanf("%d%d",&n,&m);
    int *year = malloc(sizeof(int)*m);
    int *city = malloc(sizeof(int)*m);
    int *num = malloc(sizeof(int)*m);
    int *haya2 = malloc(sizeof(int)*m);

    int *haya = malloc(sizeof(int)*(n+1));

    for (SINT32 i = 0; i < m; i++) {
        city[i] = 0;
        year[i] = 0;
        num[i] = 0;
        haya2[i] = 0;
    }
    for (SINT32 i = 1; i < n+1; i++) {
        haya[i] = 0;
    }


    for (SINT32 i = 0; i < m; i++) {
        scanf("%d%d", &city[i],&year[i]);
        num[i] = i;
    }

    quick_sort(year,city,num, 0, m-1);

    for (SINT32 i = 0; i < m; i++) {
        haya[city[i]] = haya[city[i]] + 1;
        haya2[i] = haya[city[i]];
    }
/*
    for (SINT32 i = 0; i < m; i++) {
        printf("%d ",num[i]);
    }
    printf("\n");
    */

    quick_sort(num,city,haya2, 0, m-1);
/*
    for (SINT32 i = 0; i < m; i++) {
        printf("%d ",num[i]);
    }
    printf("\n");
    */


    for (SINT32 i = 0; i < m; i++) {
        printf("%06d%06d\n",city[i],haya2[i]);
    } 

    
	return 0;
}