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: Wrong Answer)

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<cmath>
#include<cstdlib>
#include<tuple>
#include<iomanip>
#include<map>
#include<queue>
#define int long long
using namespace std;

int swap(int a,int b) {
	int tmp;
	tmp = a;
	a = b;
	b = tmp;
}
signed main() {
	int N,M;
	cin >> N >> M;
	vector<tuple<int,int,int>> vec(M + 1);
	for(int i = 1;i < M + 1;i++) {
		int A,B;
		cin >> A >> B;
		vec.at(i) = make_tuple(A,B,i);
	}
	get<0>(vec.at(0)) = 0;
	sort(vec.begin(),vec.end());
	int A = 1;
	for(int i = 1;i < M + 1;i++) {
		if(get<0>(vec.at(i - 1)) != get<0>(vec.at(i))) {
			A = 1;
		}
		get<1>(vec.at(i)) = A;
      	A++;
	}
	for(int i = 1;i < M + 1;i++) {
		int tmp = get<0>(vec.at(i));
		get<0>(vec.at(i)) = get<2>(vec.at(i));
		get<2>(vec.at(i)) = tmp;
	}
	sort(vec.begin(),vec.end());
	for(int i = 1;i < M + 1;i++) {
		int X = get<2>(vec.at(i));
		int Y = get<1>(vec.at(i));
		string S1 = to_string(X);
		string S2 = to_string(Y);
		for(int j = S1.size();j < 6;j++) {
			S1.insert(0,"0");
		}
		for(int j = S2.size();j < 6;j++) {
			S2.insert(0,"0");
		}
		cout << S1 << " " << S2 << endl;
	}
}