#include <algorithm>
#include <iostream>
using namespace std;

int main() {
    string s, cur, temp;
    cin >> s;

    if (s.length() == 1) {
        cout << s.length();
        return 0;
    }

    int len = 0;
    for (int i = 0; i < s.size(); ++i) {
        for (int j = i + 1; j < s.size(); ++j) {
            cur = s.substr(i, j - i + 1);
            temp = cur;
            reverse(cur.begin(), cur.end());
            if (cur == temp)
                len = max(len, j - i + 1);
        }
    }

    cout << len;
    return 0;
}