#include <bits/stdc++.h>

using namespace std;

string S;

bool is_palindrome(string a)
{
    int n = a.size();
    for (int i = 0; i < n / 2; ++i) if (a[i] != a[n - i - 1]) return false;
    return true;
}

int main()
{
    cin >> S;

    int ma = 0;

    for (int i = S.size() - 1; i >= 1; --i) {
        for (int j = 0; j + i <= S.size(); ++j) {
            if (is_palindrome(S.substr(j, i))) {
                ma = max(ma, i);
                break;
            }
        }
    }

    cout << ma << endl;
}