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: Accepted)

"""
import numpy as np
N, M = map(int, input().split())
cities = {}
Y = {}
for i in range(M):
    p,y = map(int, input().split())
    cities[i] = p
    Y[i] = y

ans = {}
sorted_Y = sorted(Y.items(), key=lambda x:x[1])
P_i = np.zeros(N)
for i,y in sorted_Y:
    p = cities[i]
    P_i[p-1] += 1
    ans[i] = (p, int(P_i[p-1]))

for i in range(M):
    print('{0:06}{1:06}'.format(ans[i][0], ans[i][1]))
"""

n, m = map(int,input().split())
pys = []
for i in range(m):
    x = list(map(int, input().split()))
    x = [x[0],x[1],i]
    pys.append(x)

pys.sort()
pp = -1
lid = 0
ans = [0]*m
for i in range(m):
    if pp == pys[i][0]:
        lid += 1
    else:
        lid = 1
        pp = pys[i][0]
    ans[pys[i][2]] = pp*10**6+lid

for v in ans:
    print('{:012d}'.format(v))