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 JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

function main(input){
  var str = input.split('\n');
  var total = [];
  for(let i=0;i<str.length;i++){
    var str2 = str[i].split(' ');
    var int = [parseInt(str2[0]),parseInt(str2[1])]
    total.push(int);
  }
  var N = total[0][0];//県の数
  var M = total[0][1];//N個の件に存在する市の総数
  var prefuclist = [];
  var yearlist = [];
  for(let j=1;j<=M;j++){
    var prefuc = total[j][0]+'';
    var add0 = '0';
    var prefuc = add0.repeat(6-prefuc.length)+prefuc;
    prefuclist.push(prefuc);
  }
  var checkyear = [];
    for(let l=1;l<=M;l++){
      var sum = 1;
      for(let m=1;m<=M;m++){
        if(total[l][0] === total[m][0]){
          var diff = total[l][1]-total[m][1];
          if(diff >0){
            sum++;
          }//if(diff >0)
        }//if(total[l][0] === total[m][0])
      }//for(let m=1;m<=M;m++)
      checkyear.push(sum);
    }//for(let l=1;l<=M;l++)
  console.log(checkyear);
  for(let n=0;n<M;n++){
  	var year = checkyear[n]+'';
    var add0 = '0';
    var year = add0.repeat(6-year.length)+year;
    yearlist.push(year);
  }
  for(let o=0;o<M;o++){
    console.log(prefuclist[o]+yearlist[o]);
  }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));