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 <iostream>
#include<vector>
#include<algorithm>
#include <iomanip>
#include <sstream>

using namespace std;


class ID{
public:
    int i;
    int P;
    int Y;
    int ans;
};
bool cmp0(const ID &a, const ID &b){
    return a.i < b.i;
}

bool cmp1(const ID &a, const ID &b){
    return a.P < b.P;
}

bool cmp2(const ID &a, const ID &b){
    return a.Y < b.Y;
}

int main(void){
    int N,M;
    cin >> N >> M;
    vector<ID> idlist;
    idlist.resize(M);
    for(int i = 0; i < M;i++){
        cin >> idlist[i].P >> idlist[i].Y;
        idlist[i].i = i;
    }
    
    sort(idlist.begin(),idlist.end(),cmp2);
    sort(idlist.begin(),idlist.end(),cmp1);
    int imemo;
    int ians = 1;
    int flag = 0;
    for(int i = 0; i < M;i++){
        if(flag == 0){
            imemo = idlist[i].P;
            idlist[i].ans = ians; 
            ians++;
            flag = 1;
        }else if(flag == 1&&imemo == idlist[i].P){
            idlist[i].ans = ians; 
            ians++;
        }else{
            ians = 1;
            imemo = idlist[i].P;
            idlist[i].ans = ians; 
            ians++;
        }
    
    }
    
    sort(idlist.begin(),idlist.end(),cmp0);
    string s;
    for(int i = 0; i < M;i++){
        ostringstream sout;
        sout << std::setfill('0') << std::setw(6) << idlist[i].P;
        sout << std::setfill('0') << std::setw(6) << idlist[i].ans;
        s = sout.str();
        cout << s<<endl;
        //cout << idlist[i].P<<idlist[i].ans<<endl;
    }
    
    
    
}