use proconio::{input, marker::Chars};

fn solve() -> String {
  input! {
    n: Chars,
  }
  let l = n.len();
  if l == 1 {
    if n[0] == '4' {
      "4".to_owned()
    } else {
      "5".to_owned()
    }
  } else {
    if (n[0] as u8) < b'4' {
      "5".repeat(l - 1)
    } else {
      let mut mode = 0u8;
      let mut pos = 0;
      for (i, ci) in n.iter().enumerate().map(|(i, &c)| (i, c as u8 - b'0')) {
        if ci < 4 {
          mode = 1;
          pos = i;
          break;
        } else if ci > 5 {
          mode = 2;
          pos = i;
          break;
        }
      }
      match mode {
        0 => n.iter().collect::<String>(),
        1 => {
          let mut ans = vec!['5'; l];
          let mut pos5 = l;
          for i in (0..pos).rev() {
            if n[i] == '5' {
              pos5 = i;
              break;
            }
          }
          if pos5 == l {
            return "5".repeat(l - 1);
          } else {
            for i in 0..pos5 {
              ans[i] = n[i];
            }
            ans[pos5] = '4';
          }
          ans.iter().collect::<String>()
        },
        2 => {
          let mut ans = vec!['5'; l];
          for i in 0..pos {
            ans[i] = n[i];
          }
          ans.iter().collect::<String>()
        },
        _ => unreachable!(),
      }
    }
  }
}

fn main() {
  let ans = solve();
  println!("{}", ans);
}