#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <numeric>
#include <functional>
#include <set>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <climits>
#include <fstream>
#include <bitset>
#include <time.h>

#define ll long long
#define FOR(i,a,b) for(int i= (a); i<((int)b); ++i)
#define RFOR(i,a) for(int i=(a); i >= 0; --i)
#define FOE(i,a) for(auto i : a)
#define ALL(c) (c).begin(), (c).end()
#define DUMP(x)  cerr << #x << " = " << (x) << endl;
#define SUM(x) std::accumulate(ALL(x), 0L)
#define EPS 1e-14

using namespace std;


set<string> palindromes(string s) {
    set<string> palindromes;

    for (int i = 0; i < s.size(); ++i) {
        // iを中心とした回文
        int left = i;
        int right = i;
        while (0 <= left && right < s.size() && s[left] == s[right]) {
            palindromes.insert(s.substr(left, right - left + 1));
            left--;
            right++;
        }

        // iとi + 1を中心とした回文
        left = i;
        right = i + 1;
        while (0 <= left && right < s.size() && s[left] == s[right]) {
            palindromes.insert(s.substr(left, right - left + 1));
            left--;
            right++;
        }
    }

    return palindromes;
}

int main(int argc, char *argv[]) {
    string s;
    cin >> s;
    
    int ans = 0;
    FOE(p, palindromes(s)) {
        if (p.size() != s.size()) {
            ans = max<int>(ans, p.size());
        }
    }
    cout << ans << endl;

    return 0;
}