#include <bits/stdc++.h>
using namespace std;

template <typename T>
T gcd(T x, T y)
{
    if (y == 0)
        return x;
    return gcd(y, x % y);
}

template <typename T>
T lcm(T x, T y)
{
    if (x == 0 || y == 0)
        return 0;
    return x / gcd(x, y) * y;
}

int main()
{
    string s;
    cin >> s;
    int n = s.size();
    int ans = 0;
    for (int i = 0; i < n; i++)
    {
        for (int j = n - 1; j > i; j--)
        {
            if (s[i] != s[j])
                continue;
            int cnt = 0;
            int l = i, r = j;
            while (l <= r)
            {
                if (s[l] == s[r])
                    cnt += (l == r ? 1 : 2);
                l++;
                r--;
            }
            ans = max(ans, cnt);
        }
    }
    cout << ans << endl;
}