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<vector>
#include<utility>
#include<deque>
#include<algorithm>
#include <iomanip>
#include<cmath>
#include<numeric>
#include<list>
#include<sstream>

using namespace std;
using ll = long long int;
constexpr int INF = 1 << 29;
constexpr ll MOD = ll(1e9 + 7);
int n, m;
int p[100000];
ll y[100000];
vector<ll> yd[100001];

int main(void) {
	cin >> n >> m;
	for (int i = 0; i < m; i++) {
		cin >> p[i] >> y[i];
		yd[p[i]].push_back(y[i]);
	}

	for (int i = 0; i < n; i++) {
		sort(yd[i+1].begin(), yd[i+1].end());
	}

	for (int i = 0; i < m; i++) {
		int cnt = int(lower_bound(yd[p[i]].begin(), yd[p[i]].end(), y[i]) - yd[p[i]].begin()) + 1;
		cout << setw(6) << std::right << setfill('0') << p[i];
		cout << setw(6) << std::right << setfill('0') << cnt;
		cout << endl;
	}

	return 0;
}