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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <stdio.h>
#include <vector>
#include <algorithm>
#define mp make_pair
using namespace std;

double av(double a){
	if(a<0)return -a;
	return a;
}
int nod(int x){
	if(x<10)return 1;
	return 1+nod(x/10);
}
void psd(int x){
	for(int i = 0;i < 6-nod(x);i ++){
		cout<<0;
	}
	cout<<x;
}
int main(){
	int n, m, y, p;
	vector <pair<int,pair<int,int> > > yp;
	vector <pair<int,int> > op;
	cin>>n>>m;
	vector <int> nocip(n);
	op.resize(m);
	for(int i = 0;i < m;i ++){
		cin>>p>>y;
		yp.push_back(mp(y,mp(p,i)));
	}
	for(int i = 0;i < n;i ++){
		nocip[i]=0;
	}
	sort(yp.begin(),yp.end());
	for(int i = 0;i < yp.size();i ++){
		op[yp[i].second.second].first=yp[i].second.first;
		nocip[yp[i].second.first]++;
		op[yp[i].second.second].second=nocip[yp[i].second.first];
	}
	for(int i = 0;i < m;i ++){
		psd(op[i].first);
		psd(op[i].second);cout<<"\n";
	}
}