use std::collections::HashSet;
use std::error;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;


fn set_from_str(chars: &str) -> HashSet<u32> {
	HashSet::from_iter(chars.chars().map(|c| if c.is_uppercase() { c as u32 - 38 } else { c as u32 - 96 }))
}


fn main() -> Result<(), Box<dyn error::Error>> {
	let f = File::open("input.txt")?;
	let reader = BufReader::new(f);

	let mut sum: u32 = 0;

	for line in reader.lines() {
		let line = line?;
		let (c1, c2) = line.split_at(line.len() / 2);
		let c1_set = set_from_str(c1);
		let c2_set = set_from_str(c2);
		sum += c1_set.intersection(&c2_set).sum::<u32>();
	}

	println!("{}", sum);

    Ok(())
}