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)

import numpy as np


def solve(string):
    n, m, *py = map(int, string.split())
    p = [[] for _ in range(n)]
    for _p, _y in zip(py[0::2], py[1::2]):
        p[_p - 1].append(_y)
    for i in range(n):
        p[i] = np.argsort(np.argsort(p[i]))
    counter = [0 for _ in range(n)]
    ans = []
    for _p, _y in zip(py[0::2], py[1::2]):
        t = "{:06}{:06}".format(_p, p[_p - 1][counter[_p - 1]] + 1)
        ans.append(t)
        counter[_p - 1] += 1
        p[i] = np.argsort(np.argsort(p[i]))
    return "\n".join(ans)


if __name__ == '__main__':
    n, m = map(int, input().split())

    print(solve("{} {}\n".format(n, m) + "\n".join([input() for _ in range(m)])))