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>

typedef struct{
    int P;
    int Y;
    int x;
}ID;

void SortBubble(int array[],int n){
    int i,j,temp;
    for (i = 0;i < n - 1;i++) {
        for (j = 0;j < n - 1;j++) {
            if (array[j + 1] < array[j]) {
                temp = array[j];array[j] = array[j + 1];array[j + 1] = temp;
            }
        }
    }
}

int main(){
    int N,M;
    scanf("%d%d",&N,&M);
    ID A[M];
    for(int i = 0;i < M;i++){
        scanf("%d%d",&A[i].P,&A[i].Y);
    }
    int PreYear[N][M];
    int count[N];
    for(int i = 0;i < N;i++)count[i] = 0;
    for(int i = 0;i < N;i++){
        for(int j = 0;j < M;j++){
            PreYear[i][j] = 1000000000;
        }
    }
    for(int i = 0;i < M;i++){
        for(int j = 1;j <= N;j++){
            if(A[i].P == j){
                PreYear[j][count[j]] = A[i].Y;
                count[j]++;
            }
        }
    }
    for(int i = 0;i < N;i++)SortBubble(PreYear[i],M);

    for(int i = 0;i < M;i++){
        for(int j = 1;j <= N;j++){
            for(int k = 0;k < M;k++)
            if(A[i].P == j && A[i].Y == PreYear[j][k]) A[i].x = k + 1;
        }
    }
    
    for(int i = 0;i < M;i++){
        printf("%06d%06d\n",A[i].P,A[i].x);
    }
    return 0;
}