#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

int main()
{
    string s;
    cin >> s;
    int n = s.size();

    int ans = 0;
    for(int i=0; i<2*n-1; ++i){
        int a = i / 2;
        int b = (i + 1) / 2;

        int len = b - a - 1;
        while(0 <= a && b < n){
            if(s[a] == s[b])
                len += 2;
            -- a;
            ++ b;
        }
        ans = max(ans, len);
    }
    cout << ans << endl;

    return 0;
}