#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> pip;
const ll INF = 1e9+100;
const ll MOD = 1e9+7;
const double EPS  = 1e-10;
const bool debug = 0;
//---------------------------//

string s;

int main() {
	cin >> s;
	
	int ans = INF;
	
	REP(i, s.size()) {
		int base = max(i, (int)s.size() - i - 1) - min(i, (int)s.size() - i - 1); // 中心を含む場合
		
		int l = i - 1, r = i + 1;
		int now = 0;
		while (l >= 0 && r < s.size()) {
			if (s[l] != s[r]) now += 2;
			l--; r++;
		}
		chmin(ans, now + base);
		
		l = i; r = i + 1;
		now = 0;
		while (l >= 0 && r < s.size()) {
			if (s[l] != s[r]) now += 2;
			l--; r++;
		}
		if (l >= 0) now += l + 1;
		if (r < s.size()) now += s.size() - r;
		
		chmin(ans, now);
	}
	ans = s.size() - ans;
	cout << ans << endl;
	
	return 0;
}