use std::fs::File;
use std::io::prelude::*;


fn main() -> std::io::Result<()> {
    let mut file = File::open("numbers.txt")?;
    let mut content = String::new();
    file.read_to_string(&mut content)?;

    let mut sum = 0u64;

    for line in content.lines() {
        let first_10 = &line[0..11];
        if let Ok(num) = first_10.parse::<u64>() {
            sum = sum + num;
        }
    }
    let answer = &sum.to_string()[0..10];
    println!("{}", answer);
    Ok(())
}