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 LuaJIT (2.0.4) (judge verdict: Accepted)

local n,m=io.read("*n","*n")
local city={}
for i=1,m do
    local p,y=io.read("*n","*n")
    city[i]={p,y,i}
end

table.sort(city,function(x,y)
    if x[1]~=y[1] then
        return x[1]<y[1]
    else
        return x[2]<y[2]
    end
end)

local id={}
local x=1
local P=0
for i=1,m do
    local p=city[i][1]
    local y=city[i][2]
    local c=city[i][3]
    if P==p then
        x=x+1
    else
        x=1
    end
    id[c]=string.format("%06d",p)..string.format("%06d",x)
    P=p
end

for i=1,m do
    print(id[i])
end