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: Accepted)

#include <stdio.h>
#include <stdlib.h>
typedef struct {
    int num;
    int pref;
    int yer;
    int ID;
}unit;
int compare(const void *a,const void *b){
    unit s= *(unit*)a,t= *(unit*)b;
    int tmp1=s.yer,tmp2=t.yer;
    if(tmp1>tmp2)return 1;
    return -1;
}
int comp(const void *a,const void *b){
    unit s= *(unit*)a,t= *(unit*)b;
    int tmp1=s.num,tmp2=t.num;
    if(tmp1>tmp2)return 1;
    return -1;
}
int main()
{   int n,m;
    scanf("%d%d",&n,&m);
    unit K[m];
    int used[100001];
    for(int i=0;i<100001;i++)used[i]=1;
    
    for(int i=0;i<m;i++){
        scanf("%d%d",&K[i].pref,&K[i].yer);
        K[i].num=i;
    }
    qsort(K,m,sizeof(unit),compare);
    for(int i=0;i<m;i++){
        K[i].ID=used[K[i].pref];
        used[K[i].pref]++;
    }
    qsort(K,m,sizeof(unit),comp);
    for(int i=0;i<m;i++){
        if(K[i].pref<10){
            printf("00000%d",K[i].pref);
        }else if(K[i].pref<100){
            printf("0000%d",K[i].pref);
        }else if(K[i].pref<1000){
            printf("000%d",K[i].pref);
        }else if(K[i].pref<10000){
            printf("00%d",K[i].pref);
        }else if(K[i].pref<100000){
            printf("0%d",K[i].pref);
        }else{
            printf("%d",K[i].pref);
        }
        if(K[i].ID<10){
            printf("00000%d",K[i].ID);
        }else if(K[i].ID<100){
            printf("0000%d",K[i].ID);
        }else if(K[i].ID<1000){
            printf("000%d",K[i].ID);
        }else if(K[i].ID<10000){
            printf("00%d",K[i].ID);
        }else if(K[i].ID<100000){
            printf("0%d",K[i].ID);
        }else{
            printf("%d",K[i].ID);
        }
        printf("\n");
    }

    return 0;
}