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;
        
        void output(int X){
              string A;
              A=to_string(X);  
              for(int i=1; i<= 6- A.size(); i++ ){
                    cout<<0;
              }
              cout<<A; 
        }

        int main() {    
             
             int N, M; 
             cin>> N >> M;
             
             priority_queue<tuple<int,int,int>> pq;
             
             for(int i=0; i<M; i++){
                   int P, Y; 
                   cin >> P >> Y;
                   pq.push( make_tuple(-P,-Y,-i) ); 
             }
             
             priority_queue<tuple<int,int,int>> qr;
             
             int p=0;
             int y=1; 
             while(pq.size()>0){
                  int a, b, c;
                  tie(a,b,c) = pq.top();  
                  if(p==a) y++; 
                  if(p!=a) y=1; 
                  pq.pop(); 
                  
                  qr.push(make_tuple(c,a,y)); 
                  p=a;
             }
             
             while(qr.size()>0){
                  int d, e, f;
                  tie(d,e,f) = qr.top();
                  qr.pop(); 
                  output(-e);
                  output(f); 
                  cout<< endl; 
             }
             
             
             
        }