#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
#include <string>
#include <stack>
typedef long long ll;
#define MOD 1000000007
using namespace std;

int main(){
    string S;
    int ans = 0;
    cin >> S;
    for(int center = 0; center < (int)S.length(); center++)
    {
        int left, right, cnt = 1;
        left = center - 1;
        right = center + 1;
        while (left >= 0 && right < (int)S.length()) {
            if (S[left--] == S[right++]) {
                cnt += 2;
            }
        }
        ans = max(ans, cnt);
    }
    for(int center = 0; center < (int)S.length() - 1; center++) {
        int left, right, cnt = 0;
        left = center;
        right = center + 1;
        while (left >= 0 && right < (int)S.length()) {
            if (S[left--] == S[right++]) {
                cnt += 2;
            }
        }
        ans = max(ans, cnt);
    }
    cout << ans << endl;
    return 0;
}