#![allow(
    non_snake_case,
    unused_variables,
    unused_assignments,
    unused_mut,
    unused_imports,
    unused_macros,
    dead_code,
    static_mut_refs
)]

// use ac_library::*;
// use ascii::AsciiChar::N;
use itertools::Itertools;
use proconio::{derive_readable, input, marker::*};
// use rustc_hash::*;
use std::{cmp::*, collections::*, fmt::*, hash::*, marker::PhantomData, ops::*, println};

fn main() {
    input! {
        mut S: Chars,
    }
    let mut ans = Vec::new();

    if S.len() == 1 && S[0] == '4' {
        println!("{}", '4');
        return;
    }
    // 最初が4未満なら確定
    if S[0].to_digit(10).unwrap() < 4 {
        println!("{}", "5".repeat(S.len() - 1));
        return;
    }
    const INF: usize = 3_000_000_000_000_000_000;
    let mut mode = false;
    let mut lsfiv = INF;
    for i in 0..S.len() {
        if S[i].to_digit(10).unwrap() > 5 || mode {
            ans.push('5');
            mode = true;
            lsfiv = i;
        } else if S[i].to_digit(10).unwrap() < 4 {
            if lsfiv != INF {
                ans[lsfiv] = '4';
                // dbg!(&)
                for j in (lsfiv + 1)..i {
                    ans[j] = '5';
                }
                ans.push('5');
                mode = true;
            } else {
                println!("{}", "5".repeat(S.len() - 1));
                return;
            }
        } else if S[i] == '5' {
            ans.push('5');
            lsfiv=i;
        } else {
            assert!(S[i]=='4');
            ans.push('4');
        }
    }

    for a in ans {
        print!("{}",a);
    }
    println!();
}

trait Pipe: Sized {
    fn pipe<F, T>(self, f: F) -> T
    where
        F: FnOnce(Self) -> T,
    {
        f(self)
    }
}
impl<T> Pipe for T {}

fn yesno(b: bool) {
    if b {
        println!("Yes");
    } else {
        println!("No");
    }
}