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 math

def Show(n):
	s = str(n)
	m = len(s)
	for i in range(6 - m):
		print("0",end = "")
	print("{0}".format(n),end = "")

class city:
	year = 0
	p = 0
	number = 0
	def __init__(self,y,pi,n):
		self.year = y
		self.p = pi
		self.number = n

s = input().split()
n = int(s[0])
m = int(s[1])
cities = []
for i in range(m):
	s = input().split()
	p = int(s[0])
	y = int(s[1])
	cities.append(city(y,p,i))
x = [[] for i in range(n)]
for i in range(m):
	x[cities[i].p - 1].append(cities[i])
for i in range(n):
	x[i].sort(key = lambda x : x.year)
ans = []
for i in range(m):
	ans.append([0,0])
for i in range(n):
	for j in range(len(x[i])):
		ans[x[i][j].number][0] = x[i][j].p
		ans[x[i][j].number][1] = j + 1
for i in range(m):
	Show(ans[i][0])
	Show(ans[i][1])
	print()