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 Python (3.4.3) (judge verdict: Time Limit Exceeded)

n = list(map(int, input().split()))
N, M = n[0], n[1]

import numpy as np

def main():
    M_list = []
    y_array = np.array([[10000000000]*M]*N)
    for i in range(M):
        tmp = list(map(int, input().split()))
        M_list.append(tmp[0])
        y_array[tmp[0]-1,i] = tmp[1]

    num_array = np.zeros([N,M])
    ynum_array = np.ones([N,M])
    for k in range(N):
        #print(np.argsort(y_array[k]))
        num_array[k,:] = np.argsort(y_array[k])
        y_sorted = np.sort(y_array)
        tmp = 1
        for l in np.argsort(y_array[k]):
            if int(ynum_array[k][l]) == 10000000000:
                break
            ynum_array[k][l] = tmp
            tmp += 1

    for j in range(M):
        ac = (str(M_list[j]).zfill(6)) + (str(int(ynum_array[M_list[j]-1][j])).zfill(6))
        print(ac)
        
    #print(y_array)

if __name__ == '__main__':
    main()