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 <fstream>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <functional>
#include <stack>
#include <queue>
#include <string>
#include <map>
#include <unordered_map>
#include <bitset>
#include <numeric>
#include <vector>
#include <set>
#include <unordered_set>
#include <bitset>
#include <limits>
#include <random>
#include <complex>
#include <numeric>


using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;

const ll mod=1000000007ll;
const ll inf=1000000000000000ll;

const ll nmax=50;


int main(){
    ll n,m;
    cin>>n>>m;
    ll p[m],y[m];
    vector<ll> v[n];
    for(ll i=0;i<m;i++){
        cin>>p[i]>>y[i];
        p[i]--;
        v[p[i]].push_back(y[i]);
    }
    for(ll i=0;i<n;i++){
        sort(v[i].begin(),v[i].end());
    }
    for(ll i=0;i<m;i++){
//        cout<<p[i]<<" "<<y[i]<<endl;
        vector<ll>::iterator it = lower_bound(v[p[i]].begin(), v[p[i]].end(), y[i]);
        cout << setw(6) << setfill('0') << p[i]+1 << setw(6) << setfill('0') << (it - v[p[i]].begin())+1<<endl;
    }
    //for(ll i=0;i<2;i++)cout<<v[0][i]<<endl;

    return 0;
}