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 PyPy3 (2.4.0) (judge verdict: Accepted)

N, M = map(int, input().split())
cities = []
for i in range(0, M):
	P, Y = map(int, input().split())
	cities.append([i, P, Y])
cities.sort(key = lambda v: v[2])
cities.sort(key = lambda v: v[1])
idkeylist = [[cities[0][0], cities[0][1], 1]]
cnt = 2
for i in range(1, M):
	if cities[i][1] != idkeylist[-1][1]:
		idkeylist.append([cities[i][0], cities[i][1], 1])
		cnt = 2
	else:
		idkeylist.append([cities[i][0], cities[i][1], cnt])
		cnt += 1
idkeylist.sort(key = lambda v: v[0])
for i in range(0, M):
	ansP = str(idkeylist[i][1])
	while len(ansP) < 6:
		ansP = '0' + ansP
	ansT = str(idkeylist[i][2])
	while len(ansT) < 6:
		ansT = '0' + ansT
	print(ansP+ansT)