fn main() -> Result<(), std::io::Error> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let input_str = s.trim();

    let mut ans = -1;
    for (id, i) in input_str.chars().enumerate() {
        if id == 0 {
            if i != '1' {
                ans = -1;
                break
            }
        } else {
            if i == '3' {
                ans += 1;
            } else {
                ans = -1;
                break;
            }
        }
    }
    println!("{}", ans);

    Ok(())
}