#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#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>
using namespace std;

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

    int ans = 0;
    for(int i=0; i<n; ++i){
        for(int j=i; j<n; ++j){
            int len = j - i + 1;
            if(len == n)
                continue;
            string a = s.substr(i, len);
            string b = a;
            reverse(b.begin(), b.end());
            if(a == b)
                ans = max(ans, len);
        }
    }
    cout << ans << endl;

    return 0;
}