#include <iostream>
#include <string>

using namespace std;

int SearchPalidrome(string, int);

int main(int argc, const char * argv[]) {
    string sentence;
    int maxLength = 0;
    
    cin >> sentence;
    
    for (int i = 0; i < sentence.length() - 1; i++){
        for (int j = i; j < sentence.length(); j++) {
            string temp =sentence.substr(i, sentence.length() - j);
            int num = SearchPalidrome(temp, 0);
            if(num == sentence.length())
                num -= 2;
            if (num > maxLength)
                maxLength = num;
        }
    }
    
    cout << maxLength << endl;
    
    return 0;
}

int SearchPalidrome(string sentence, int layer) {
    if (sentence.length()== 1)
        return ++layer;
    if (sentence.length()== 0)
        return layer;
    
    if (sentence[0] == sentence[sentence.length() - 1]) {
        string temp =sentence.substr(1, sentence.length() - 2);
        return SearchPalidrome(temp, layer += 2);
    }
    
    return 0;
}