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 Lua (5.3.2) (judge verdict: Wrong Answer)

local sheng = io.read("*n")
local shi = io.read("*n")

local tab = {}
local tab1 = {}
local t = {}

for i=1,shi do
	local s1 = io.read("*n")
	local s2 = io.read("*n")
	if not tab[s1] then
		tab[s1] = {}
	end
	table.insert(tab[s1], {s1, s2, i})
	tab1[s1] = true
end

for v,_ in pairs(tab1) do
	print("--- show v", v, tab[v])
	table.sort(tab[v], function(a,b)
		return a[2] < b[2]
	end)
	for i,v in ipairs(tab[v]) do
		t[v[3]] = string.format("%06d%06d", v[1], i)
	end
end

for i,v in ipairs(t) do
	print(v)
end