#include <fstream>
#include <cstring>

using namespace std;

#define MAX_N 510

ifstream f("palm.in");
ofstream g("palm.out");

int n;

char s[MAX_N];

int main() {

    f >> s; n = strlen(s);

    int sol = 1;

    for (int i = 0; i < n; i++) { 
        //lungime impara
        for (int j = 2; 0 <= i - j + 1 && i + j - 1 < n; j++)
            if (s[i - j + 1] == s[i + j - 1] && s[i - j + 1] <= s[i - j + 2])
                sol = (sol < 2 * j - 1) ? 2 * j - 1 : sol;
            else
                break;

        //lungime para
        for (int j = 1; 0 <= i - j + 1 && i + j < n; j++)
            if (s[i - j + 1] == s[i + j] && s[i - j + 1] <= s[i - j + 2])
                sol = (sol < 2 * j) ? 2 * j : sol;
            else
                break;
    }

    g << sol << "\n";

    return 0;
}