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 i,pre,ans;
		long year;
} prefecture;

int cmp_year( const void *p, const void *q ) {
    return ((prefecture*)p)->year - ((prefecture*)q)->year;
}

int cmp_i( const void *p, const void *q ) {
    return ((prefecture*)p)->i - ((prefecture*)q)->i;
}



int main(){
	int n,m,i,j,ban[100000]={0};
	int ans[100000][2];
	scanf("%d%d",&n,&m);
	prefecture p[m];
	for(i=0;i<m;i++){
		scanf("%d%ld",&p[i].pre,&p[i].year);
		p[i].i=i;
		ans[i][0]=p[i].pre;
	}
	qsort(p,m,sizeof(prefecture),cmp_year);	
	for(i=0;i<m;i++){
//		printf("%ld\n",y[i]);
/*		for(j=0;j<m;j++){
			if(ycpy[j]==y[i]){
				ban[p[j]-1]++;
				ans[j][1]=ban[p[j]-1];
			}
		}*/
		ban[p[i].pre-1]++;
		p[i].ans=ban[p[i].pre-1];
	}qsort(p,m,sizeof(prefecture),cmp_i);	
	for(i=0;i<m;i++)printf("%06d%06d\n",ans[i][0],p[i].ans);
	return 0;
}