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 Rust (1.42.0) (judge verdict: Accepted)

// use proconio::marker::Chars;
use proconio::{fastout, input};
// use std::cmp::{max, min};

#[fastout]
fn main() {
    input! {
        n: usize,
        m: usize,
    };

    let mut v: Vec<(u128, u128, u128)> = Vec::new();
    let mut result = vec![String::new(); m];

    for i in 0..m {
        input! {
            p: u128,
            y: u128
        }
        v.push((p, y, i as u128));
    }

    v.sort_by(|a, b| a.0.cmp(&b.0).then(a.1.cmp(&b.1)));

    let mut city = vec![1; n + 1];

    for vi in v.iter() {
        result[vi.2 as usize] = format!("{0: >06}{1: >06}", vi.0, city[vi.0 as usize]);
        city[vi.0 as usize] += 1;
    }

    for result_i in result.iter() {
        println!("{}", result_i)
    }
}