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 <stdio.h>
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <sstream>
#include <complex>
#include <vector>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cstring>
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
const long double EPS = 1e-9;
const ll mod = 1e9 + 7;
const ll INF = 1e9;

#define rep(i, n) for(ll i = 0; i < n ; i++ )
#define For(i, a, b) for(ll i = (a); i < (b) ; i++ )
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

const ll MAX_N = 100000;

int main(void){
    ll N, M;
    vector<pair<ll, ll>> yp;
    vector<pair<ll, ll>> order_by_y;
    vector<pair<ll, ll>> answer;
    ll id[MAX_N + 1];
    ll p_cnt[MAX_N + 1];
    rep(i, M + 1) p_cnt[i] = 0;
    
    cin >> N >> M;
    rep(i, M){
        ll p,y;
        cin >> p >> y;
        yp.push_back(make_pair(y, p));
        order_by_y.push_back(make_pair(y, i));
    }

    sort(all(yp));
    sort(all(order_by_y));

    rep(i, M){
        ll n = yp[i].second;
        p_cnt[n] ++; 
        id[i] = 1000000 * n + p_cnt[n];
    }

    rep(i, M) answer.push_back(make_pair(order_by_y[i].second, id[i]));
    sort(all(answer));

    rep(i, M) cout << setfill('0') << right << setw(12) << answer[i].second << endl;

    return 0;
}