#include <bits/stdc++.h>
using namespace std;
#define FOR(i, n) for(int i = 0; i < (n); i++)
#define FORR(x, arr) for(auto& x:arr)
#define ITR(x, c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())
typedef long long ll;
typedef pair<int, int> P;

string s;

int main(int argc, char const *argv[]) {
	ios_base::sync_with_stdio(false);
	cin >> s;
	int ma = 1;
	FOR(i, s.size()) {
		int cnt = 1;
		for (int j = 1; i+j<s.size() && i-j>=0; j++) {
			if (s[i+j]==s[i-j]) cnt += 2;
		}
		ma = max(ma, cnt);
	}
	FOR(i, s.size()) {
		for (int j = 1; i+j<s.size(); j+=2) {
			if (s[i]==s[i+j]) {
				int cnt = 2;
				for (int k = 1; i+j+k<s.size() && i-k>=0; k++) {
					if (s[i+j+k]==s[i-k]) cnt += 2;
				}
				ma = max(ma, cnt);
			}
		}
	}
	cout  << ma << endl;
	return 0;
}