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: Runtime Error)

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;

typedef  long long ll;


int main(){
 int N, M;
  cin >> N >> M;
  vector<pair<int, int>> PY(M), ans(M);
  for(int i=0; i < M; ++i){
    cin >> PY[i].first >> PY[i].second;
    ans[i].first = PY[i].first;
    ans[i].second = 1;
    for(int j=0; j < i; ++j){
      if(PY[j].first == PY[i].first){
        if(PY[j].second < PY[i].second){
          ++ans[i].second;
        }
        else{
          ++ans[j].second;
        }
      }
    }
  }
  
  for(int i=M-1; i >= 0; ++i){
    printf("%06d%06d\n", ans[i].first, ans[i].second);
  }
 
  return 0;
}