use proconio::input;

fn main(){
    input!{
        s: String,
    }

    let n = s.len()+1;
    let mut ans = 1;
    for l in 0..n{
        for r in l+1..n{
            let a: String = (&s[l..r]).to_string();
            let b: String = a.chars().rev().collect();
            if a == b && a.len() < n-1{
                ans = ans.max(a.len());
                println!("{a}");
            }
        }
    }

    println!("{}", ans);
}