use proconio::input;
fn main() {
  input!{
    n: usize
  }

  let mut multiplier = 1;
  loop {
    let current = n*multiplier;
    if current<1_000_000_000{multiplier += 10; continue;}
    let current_str = (current/10).to_string();
    if current_str == current_str.chars().rev().collect::<String>(){
        println!("{}", current);
        return;
    }

    multiplier += 10;
  }
}