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;
using ll=long long;
using vin=vector<int>;
using vll=vector<long long>;
using vvin=vector<vector<int>>;
using vvll=vector<vector<long long>>;
using vstr=vector<string>;
using vvstr=vector<vector<string>>;
using vch=vector<char>;
using vvch=vector<vector<char>>;
using vbo=vector<bool>;
using vvbo=vector<vector<bool>>;
using vpii=vector<pair<int,int>>;
using pqsin=priority_queue<int,vector<int>,greater<int>>;
#define mp make_pair
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,s,n) for(int i=(s);i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define decp(n) cout<<fixed<<setprecision((int)n)
#define _GLIBCXX_DEBUG
const int inf=1e9+7;

int main(){
    int n,m;cin>>n>>m;
    vpii c(m);
    map<int,int> year;
    map<int,string> id;
    rep(i,m){
        int p,y;cin>>p>>y;
        c[i]=mp(p,y);
        year[i]=y;
    }
    sort(all(c));
    int tmp=1;
    int cs;
    int tmps;
    rep(i,m){
        if(i>0&&c[i].first==c[i-1].first){
            tmp++;
            string s;
            cs=to_string(c[i].first).size();
            tmps=to_string(tmp).size();
            rep(j,6-cs)s+='0';
            s+=to_string(c[i].first);
            rep(j,6-tmps)s+='0';
            s+=to_string(tmp);
            id[c[i].second]=s;
        }
        else{
            tmp=1;
            string s;
            cs=to_string(c[i].first).size();
            rep(j,6-cs)s+='0';
            s+=to_string(c[i].first);
            s+="000001";
            id[c[i].second]=s;
        }
    }
    rep(i,m)cout<<id[year[i]]<<endl;
}