#![allow(unused_imports)]
#![allow(non_snake_case)]
use std::collections::HashMap;
use std::collections::HashSet;
use std::collections::VecDeque;

#[allow(unused_macros)]
macro_rules! read {
    ([$t:ty] ; $n:expr) =>
        ((0..$n).map(|_| read!([$t])).collect::<Vec<_>>());
    ($($t:ty),+ ; $n:expr) =>
        ((0..$n).map(|_| read!($($t),+)).collect::<Vec<_>>());
    ([$t:ty]) =>
        (rl().split_whitespace().map(|w| w.parse().unwrap()).collect::<Vec<$t>>());
    ($t:ty) =>
        (rl().parse::<$t>().unwrap());
    ($($t:ty),*) => {{
        let buf = rl();
        let mut w = buf.split_whitespace();
        ($(w.next().unwrap().parse::<$t>().unwrap()),*)
    }};
}

#[allow(dead_code)]
fn rl() -> String {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).unwrap();
    buf.trim_end().to_owned()
}

fn main() {
    let s = read!(String);
    let s: Vec<char> = s.chars().collect();

    let mut max = 1;
    let len = s.len();
    for start in 0..len - max {
        for end in start + max + 1..=len {
            if is_palindrome(&s[start..end]) {
                let l = end - start;
                if l != len {
                    max = l;
                }
            }
        }
    }
    println!("{}", max);
}

fn is_palindrome(s: &[char]) -> bool {
    let mut flg = true;
    let len = s.len();
    for i in 0..len / 2 {
        flg &= s[i] == s[len - 1 - i];
    }
    flg
}