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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <limits.h>
#include <string.h>
#define ll long long int

typedef struct
{
 ll P;
 ll Y;
}arr;


int cmpfunc(const void * a, const void * b)
{
  arr *orderA = (arr *)a;
  arr *orderB = (arr *)b;

  return (orderA->Y - orderB->Y);
}

int cmpfunc2(const void * a, const void * b)
{
  arr *orderA = (arr *)a;
  arr *orderB = (arr *)b;

  return (orderA->P - orderB->P);
}

int main()
{

    ll F = 100001;
    ll res[F];
   memset(res,0,sizeof(res[0]) * F);

   ll ERG = 1000000000000;

   ll N , M;
   scanf("%lld %lld",&N,&M);

   arr array[M];
   arr copy[M];
   for (ll i = 0;i<M;i++)
   {
    scanf("%lld %lld",&(array[i].P),&(array[i].Y));
    copy[i].P=array[i].P;
    copy[i].Y=array[i].Y;
   }

   qsort(array, M, sizeof(arr), cmpfunc2);
   qsort(array, M, sizeof(arr), cmpfunc);

   ll index = 0;
   ll A;
   ll TOP=1;
   for (ll i = 0;i<M;i++)
   {
      A = array[i].P * 1e+6;
      ERG = ERG + A + TOP;
      if (array[i].P==array[i+1].P && (i+1)!=M)TOP++;
      else TOP=1;
      int indice = array[i].Y;
      res[indice]=ERG;

      ERG = 1000000000000;
   }

   char str[12];
   const int c = M;
   for (int i = 0;i<c;i++)
   {
     int indice = copy[i].Y;
     sprintf(str,"%lld",res[indice]);
      for (int j = 1;j<=12;j++)
        printf("%c",str[j]);
     str[0]='\0';
     printf("\n");
   }

  return 0;
}