fn main() {
    let mut temp = String::new();
    std::io::stdin().read_line(&mut temp).ok();
    let temp = temp.trim().chars().map(|c| c as usize - '0' as usize).collect::<Vec<_>>();

    let maxval = *temp.iter().max().unwrap();
    let minval = *temp.iter().min().unwrap();
    println!("{}", maxval - minval);
}