use std::cmp::max;

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 result: usize = 1;
    for idx in 0..s.len() {
        let mut width = 1;
        let mut val = 0;
        while idx >= width && idx + width < s.len() {
            if s[idx - width] == s[idx + width] && s[idx - width] != ' ' {
                val += 2;
            }
            width += 1;
        }
        result = max(result, val + 1);
        width = 1;
        val = 0;
        while idx >= width && idx + width - 1 < s.len() {
            if s[idx - width] == s[idx + width - 1] && s[idx - width] != ' ' {
                val += 2;
            }
            width += 1;
        }
        result = max(result, val);
    }
    println!("{}", result);
}