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<bits/stdc++.h>
using namespace std;
#define LL long long
#define pii pair<int,int>
#define mx 5000
#define fori0(i,n) for(int i=0;i<n;i++)
int countdigit(int n){
    int cnt = 0;
    while(n){
        int tmp = n%10;
        cnt++;
        n -= (tmp);
        n /= 10;
    }
    return cnt;
}
string retstr(int n){
    string str;
    while(n){
        int tmp = n%10;
        str += (char)(tmp + '0');
        n -= tmp;
        n /= 10;
    }
    reverse(str.begin(),str.end());
    return str;
}
int main() {
    /*int a = 12323;
    string str = retstr(a);
    cout << str << endl;*/
    int n,m;
    cin >> n >> m;
    vector<pii> vp1(m);
    fori0(i,m){
        int x,y;
        cin >> x >> y;
        vp1[i].first = y;
        vp1[i].second = x;
    }
    vector<pii> vp = vp1;
    sort(vp.begin(),vp.end());

    for(auto x : vp) cout << x.first << " " << x.second << endl;
    map<pii,string> mp;
    int tmp = 1;
    for(int i=0;i<m;i++){
        string str = "";
        int digit = countdigit(vp[i].second);
        int zero = 6-digit;
        for(int j=1;j<=zero;j++) str += '0';
        str += retstr(vp[i].second);
        digit = countdigit(tmp);
        zero = 6-digit;
        for(int j=1;j<=zero;j++) str += '0';
        str += retstr(tmp);
        if(i+1!=m){
            if(vp[i].second != vp[i+1].second) tmp=1;
            else tmp++;
        }
        pii pp;
        pp.first = vp[i].first;
        pp.second = vp[i].second;
        mp[pp] = str;
    }

    for(auto x : vp1){
        pii pp;
        pp.first = x.first;
        pp.second = x.second;
        cout << mp[pp] << endl;
    }
    return 0;
}