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 (1.15.1) (judge verdict: Time Limit Exceeded)


use std::io::*;
use std::str::FromStr;

pub fn read<T: FromStr>() -> T {
  let stdin = stdin();
  let stdin = stdin.lock();
  let token: String = stdin
    .bytes()
    .map(|c| c.expect("failed to read char") as char)
    .skip_while(|c| c.is_whitespace())
    .take_while(|c| !c.is_whitespace())
    .collect();
  token.parse().ok().expect("failed to parse token")
}

fn main() {
  let n = read::<usize>();
  let m = read::<i32>();
  let mut pm: Vec<(i32, i32)> = vec![];
  let mut vec_t: Vec<Vec<i32>> = vec![vec![]; n];

  for _ in 0..m {
    let p = read::<i32>();
    let m = read::<i32>();
    pm.push((p, m));
    vec_t[(p - 1) as usize].push(m)
  }

  for i in 0..vec_t.len() {
    vec_t[i].sort();
  }

  for (p, m) in pm {
    let p_num: String = format!("{:0>keta$}", p, keta = 6 as usize);
    let m_num: String = format!(
      "{:0>keta$}",
      vec_t[(p - 1) as usize]
        .iter()
        .enumerate()
        .find(|&x| x.1 == &m)
        .unwrap()
        .0
        + 1,
      keta = 6 as usize
    );

    println!("{}{}", p_num, m_num);
  }
}