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: Accepted)


use std::cmp::Ordering;
use std::collections::BinaryHeap;

#[derive(PartialEq, Eq, Debug)]
struct Data {
    i: usize,
    p: usize,
    y: usize,
}

impl Ord for Data {
    fn cmp(&self, other: &Data) -> Ordering {
        if self.p != other.p {
            self.p.cmp(&other.p)
        } else {
            self.y.cmp(&other.y)
        }
    }
}

impl PartialOrd for Data {
    fn partial_cmp(&self, other: &Data) -> Option<Ordering> {
        Some(other.cmp(&self))
    }
}

fn func(input_str: &str) {
    let mut iter = input_str.split_whitespace();
    let _: usize = iter.next().unwrap().parse().unwrap();
    let m: usize = iter.next().unwrap().parse().unwrap();
    let mut bheap = BinaryHeap::new();
    for i in 0..m {
        let p: usize = iter.next().unwrap().parse().unwrap();
        let y: usize = iter.next().unwrap().parse().unwrap();
        bheap.push(Data {i: i, p: p, y: y});
    }
    let mut p_x = vec![(0, 0); m];
    let mut pre_p = None;
    let mut cnt = 1;
    while !bheap.is_empty() {
        let Data {i, p, y: _} = bheap.pop().unwrap();
        match pre_p {
            None => pre_p = Some(p),
            Some(x) => {
                if x != p {
                    cnt = 1;
                    pre_p = Some(p);
                }
                else {
                    cnt += 1;
                }
            },
        }
        p_x[i] = (p, cnt);
    }
    for (p, x) in p_x {
        println!("{:>06}{:>06}", p, x);
    }
}

use std::io::Read;

fn main() {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).unwrap();
    func(&buf[..]);
}