use std::cmp::{max, min};

fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s: Vec<char> = s.trim().chars().collect();
    
    let mut maxlen: usize = 1;
    for i in 0..s.len() {
        let mut temp: usize = 1;
        //odd
        for j in 0..min(s.len()-i-1, i) {
            if s[i - j - 1] == s[i + j + 1] {
                temp += 2;
            } else {
                break;
            }
        }
        maxlen = max(maxlen, temp);
        if i == 0 { continue; }
        let mut temp2: usize = 0;
        //even
        for j in 1..=min(s.len()-i, i) {
            if s[i - j] == s[i + j - 1] {
                temp2 += 2;
            } else {
                break;
            }
        }
        maxlen = max(maxlen, temp2);
    }
    if maxlen == s.len() {
        if   s.iter().skip(1).map(|c| (*c).to_string()).collect::<Vec<String>>().join("") == s.iter().skip(1).rev().map(|c| (*c).to_string()).collect::<Vec<String>>().join("")
          || s.iter().take(s.len()-1).map(|c| (*c).to_string()).collect::<Vec<String>>().join("") == s.iter().rev().skip(1).map(|c| (*c).to_string()).collect::<Vec<String>>().join("")
        {
            println!("{}", s.len() - 1);
        } else {
            println!("{}", s.len() - 2);
        }
    } else {
        println!("{}", maxlen);
    }
}