#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>

using namespace std;
string s;

int func(int start,int end){

	vector<char> p;

	for(int i=start; i<=end; i++){
		p.push_back(s[i]);
	}
	int count=0;

	for(int i=0; i<p.size();i++){
		if(p[i] == p[p.size()-1-i]){
			count++;
		}
	}
	return count;

}

int main() {

	cin >> s;

	int left_side = 0;
	int right_side = 0;
	int ans = 1;
	bool judge=false;
/*	cout << s.length() << endl;*/
	for (int k = 0; k < s.length() - 3; k++) {
		for (int i = 1; i < s.length() - 1-k; i++) {
			judge =false;
			left_side = i;
			right_side = i+k;
			int tmp = func(left_side,right_side);
			while (left_side != 0 && right_side != s.length() - 1) {
				if (s[--left_side] == s[++right_side]) {
					tmp += 2;
					judge =true;
				}
			}
			if(judge)
			ans = max(ans, tmp);
		}
	}
	if (ans == 1) {
		cout << ans << endl;
	} else {
		cout << ans << endl;
	}

	return 0;
}