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 <bits/stdc++.h>
using namespace std;

// DAME:
int main(){
    int n, m;
    cin >> n >> m;
    vector< tuple<int, int, int> > pyi(m);
    for(int i=0; i<m; i++){
        int a, b;
        cin >> a >> b;
        pyi[i] = make_tuple(a, b, i);
    }
    sort(pyi.begin(), pyi.end());
    int num = 0;
    // TIPS: tupleに格納されている値はget<i>で指定する
    int x = get<0>(pyi[0]);
    // ans {index, p, num: count}
    vector< vector<int> > ans(m, vector<int>(3));
  
    for(int i=0; i<m; i++){
        int y = get<0>(pyi[i]);
        if(x!=y){
            num = 0;
            x = get<0>(pyi[i]);
        }
        num++;
        int z = get<2>(pyi[i]);
        ans[i][0] = z;
        ans[i][1] = x;
        ans[i][2] = num;
    }

    sort(ans.begin(), ans.end());
  
    for(int i=0; i<m; i++){
        cout << setfill('0') << right << setw(6) << ans[i][1];
        cout << setfill('0') << right << setw(6) << ans[i][2];
        cout << endl;
    }
}