use std::io::Read;
use std::iter;
use std::num::{NonZero, NonZeroU32};

fn main() {
    let mut problem = parse_problem();

    println!("Parsed problem: {:?}", problem);

    println!("Count in total: {}", compute_problem(&mut problem))
}

#[derive(Debug)]
struct Problem{
    ranges: Vec<(u64, u64)>
}

#[derive(Debug)]
struct CleanedProblem{
    ranges: Vec<(u64, u64, NonZeroU32)>
}

fn parse_problem() -> Problem {
    let mut input = String::new();
    std::io::stdin().read_to_string(&mut input).expect("Failed to read input");

    let ranges = input.split(',').
        map(|x| x.split_once('-').expect("dash in there"))
        .map(|x| (x.0.parse::<u64>().expect("Parse error on 0"), x.1.parse::<u64>().expect("Parse error on 1")))
        .collect::<Vec<_>>();

    return Problem{
        ranges,
    };
}

fn compute_problem(problem: &mut Problem) -> u64 {
    //Potentialy ensure it is not overlapping
    let problem = clean_problem(problem);

    println!("Cleaned problem: {:?}", problem);

    let count = problem.ranges.iter().map(|range| compute_range(range.0, range.1)).sum::<u64>();

    return count;
}

fn clean_problem(problem: &Problem) -> CleanedProblem {
    let new_ranges = problem.ranges.iter().map(|(lower, upper)|{
        if (upper < lower){
            return vec![]
        }

        let digitCountU = count_digits(*upper);
        let digitCountL = count_digits(*lower);

        if (digitCountL == digitCountU){
            return vec![(*lower, *upper, digitCountU)];
        }

        let lowestOfDegree = lowestOfDegree(digitCountU);

        return vec![(*lower, lowestOfDegree-1, digitCountL), (lowestOfDegree, *upper, digitCountU)];
    }).flatten().collect::<Vec<_>>();

  return CleanedProblem{ranges: new_ranges};
}

fn lowestOfDegree(degree : NonZeroU32) -> u64{
    10u64.pow(degree.get() - 1)
}

fn compute_range(lower_bound: u64, upper_bound: u64) -> u64 {
    assert!(lower_bound > 0 && upper_bound > 0);
    assert!(upper_bound > lower_bound);
    assert!(count_digits(upper_bound) == count_digits(lower_bound));

    let digitCount = count_digits(upper_bound);

    if digitCount.get() % 2 != 0{
        return 0;
    }


    let halfDigitCount = NonZeroU32::new(digitCount.get() / 2).unwrap();



    let mut half = (lower_bound / 10u64.pow(halfDigitCount.get())).min(lower_bound % 10u64.pow(halfDigitCount.get()));
    let mut count = 0;

    loop{
        let whole = combine_numbers(half, halfDigitCount);
        if whole >= lower_bound && whole <= upper_bound{
            count += whole;
        }else if whole > upper_bound{
            break;
        }

        half += 1;
    }

    return count;
}

fn count_digits(mut n : u64) -> NonZeroU32{
    assert!(n > 0);
    let mut count = 0u64;

    while (n != 0){
        n = n / 10;
        count +=1 ;
    }

    return unsafe{NonZeroU32::new_unchecked(count as u32)};
}

fn combine_numbers(half : u64, degree : NonZeroU32) -> u64 {
    return half + half * 10u64.pow(degree.get() as u32)
}