output_description: Print the ID numbers for all the cities, in ascending order of indices (City
  1, City 2, ...).
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N M
      P_1 Y_1
      :
      P_M Y_M
attempt: #include<iostream>
  #include<cmath>
  #include<algorithm>
  #include<string>
  #include<map>
  #include<utility>
  #include<vector>
  using namespace std;
  typedef long long ll;
  ll deg(ll n){
      ll count = 0;
      while(n!= 0){
          n/=10;
          count++;
      }
      return count;
  }
  
  int main(){
      ll n,m;
      cin >> n >> m;
      ll y[m],p[m];
      for(int i = 0;i < m;i++) cin >> p[i] >> y[i];
      vector<pair<ll,ll> > pi(m);
      for(int i = 0;i < m;i++){
          pi[i] = make_pair(p[i],y[i]);
      }
      sort(pi.begin(), pi.end());
      map<pair<ll,ll>, ll>mp;
      int cur = 1;
      for(int i = 0;i < m;i++){
          if(i-1 >= 0)
          if(pi[i-1].first != pi[i].first){
              cur = 1;
          }
          mp[pi[i]] = cur;
          cur++;
      }
  
      for(int i = 0;i < m;i++){
          int id = mp[make_pair(p[i],y[i])];
          printf("%0.6lld ", p[i]);
          printf("%0.6d\n", id);
      } 
  
      
  }
problem_description: 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.
samples: [{"input": "2 3\n    1 32\n    2 63\n    1 12", "output": "000001000002\n    000002000001\n    000001000001\n    \n\n  * As City 1 is the second established city among the cities that belong to Prefecture 1, its ID number is 000001000002.\n  * As City 2 is the first established city among the cities that belong to Prefecture 2, its ID number is 000002000001.\n  * As City 3 is the first established city among the cities that belong to Prefecture 1, its ID number is 000001000001.\n\n* * *"}, {"input": "2 3\n    2 55\n    2 77\n    2 99", "output": "000002000001\n    000002000002\n    000002000003"}]