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

using namespace std;

int main() {

	string s;
	cin>>s;

	int left_side=0;
	int right_side=0;
	int ans =1;
	for(int i=1; i<s.length()-1;i++){
		left_side =i;
		right_side =i;
		int tmp=0;
		while(left_side !=0 && right_side !=s.length()-1){
			if(s[--left_side] == s[++right_side]){
				tmp +=2;
			}
		}
		ans = max(ans,tmp);
	}
	if(ans ==1){
		cout<<0<<endl;
	}else {
		cout<<ans+1<<endl;
	}

return 0;
}