use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let s: Vec<char> = itr.next().unwrap().chars().collect();
    let n = s.len();
    let mut ans = 1;
    for i in 0..n {
        for j in i..n {
            // s[i] ~ s[j]
            let mut ok = true;
            let r = (j - i + 1) / 2;
            for k in 0..r {
                if s[i + k] != s[j - k] {
                    ok = false;
                }
            }
            if ok && j - i + 1 != n {
                ans = std::cmp::max(ans, j - i + 1);
            }
        }
    }
    println!("{}", ans);
}