#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
const int inf = 1000000001;
const ll INF = 1e18 * 4;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<<fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };

int main() {
	string s_;
	cin >> s_;
	int n = s_.size(), i, j;
	int ans = -1;
	for (i = 0; i < n; i++) {
		string s = s_;
		int cnt = 1;
		for (j = 1; j < n; j++) {
			if (i - j < 0 || i + j >= n) {
				break;
			}
			else {
				if (s[i - j] != s[i + j]) {
					s[i - j] = s[i + j] = ' ';
				}
				else {
					cnt += 2;
				}
			}
		}
		ans = max(ans, cnt);
	}
	cout << ans << endl;
}