fn is_palindrome(s: &str) -> bool {
    let mut l = 0;
    let mut r = s.len() - 1;
    while l <= r {
        if s[l..=l] != s[r..=r] {
            return false;
        }
        l += 1;
        r -= 1;
    }
    true
}

fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim();

    for len in (2..s.len()).rev() {
        for l in 0..=(s.len() - len) {
            let r = l + len;
            if is_palindrome(&s[l..r]) {
                println!("{len}");
                return;
            }
        }
    }

    println!("1");
}