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)

N,M = [int(s) for s in input().split()]
data = [[0 for i in range(4)] for j in range(M)]

for i in range(M):
    l = [int(s) for s in input().split()]
    data[i][0],data[i][1] = l[0],l[1]
    data[i][2] = i+1
data.sort()

seq = 1
for i in range(M):
    if i == 0:
        data[0][3] =str(data[0][0]).zfill(6) + "000001"
        seq += 1
    elif data[i][0] == data[i-1][0]:
        data[i][3] = str(data[i][0]).zfill(6) + str(seq).zfill(6)
        seq += 1
    else:
        seq = 1
        data[i][3] = str(data[i][0]).zfill(6) + "000001"
        seq += 1

data.sort(key = lambda x:x[2])
for i in range(M):
    print(data[i][3])