use std::io::*;
use utils::*;

pub fn main() {
    let i = stdin();
    let mut o = Vec::new();
    run(i.lock(), &mut o);
    stdout().write_all(&o).unwrap();
}

fn run<R: BufRead, W: Write>(i: R, o: &mut W) {
    let mut i = ReadEx::from(i);
    let s = i.read_line();
    writeln!(o, "{}", solve(s)).unwrap();
}
fn solve(s: &str) -> String {
    fn decode(c: u8, i: usize) -> u8 {
        let b = 'A' as u8;
        let c = c - b;
        let i = ((i + 1) % 26) as u8;
        (c + 26 - i) % 26 + b
    }

    let s = s.as_bytes();
    let mut r = Vec::new();
    for i in 0..s.len() {
        r.push(decode(s[i], i));
    }
    String::from_utf8(r).unwrap()
}

mod utils {
    use super::*;

    pub struct ReadEx<R: BufRead> {
        r: R,
        s: String,
    }
    impl<R: BufRead> ReadEx<R> {
        pub fn from(r: R) -> Self {
            ReadEx {
                r: r,
                s: String::new(),
            }
        }
        pub fn read_line(&mut self) -> &str {
            self.s.clear();
            self.r.read_line(&mut self.s).unwrap();
            self.s.trim()
        }
    }
}