use proconio::input;

fn main() {
    input! {
        n: usize,
    }

    let mut start = 1e9 as usize / n + 1;
    while start % 10 != 1 {
        start += 1;
    }

    for i in (start..).step_by(10) {
        let num = n * i;
        if num < 1e9 as usize {
            continue;
        }

        let mut s = num.to_string();
        s.pop();
        if s.chars().eq(s.chars().rev()) {
            println!("{}", num);
            break;
        }
    }
}