#include <bits/stdc++.h>
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <queue>
#include <cctype>
#include <stdio.h>
#include <map>
#include <string.h>
#include <utility>

typedef long long ll;
using namespace std;

typedef pair<int, int> P;



int main() {

	string s;
	cin>>s;

	int ans =0;

	for(int i=0; i<s.length()-1; i++){
		for(int j=i+1; j<s.length(); j++){
			string tmp = s.substr(i,j-i+1);

			string reve =tmp;

			reverse(reve.begin(),reve.end());

			if(tmp == reve){
				int a = tmp.length();
				ans = max(ans,a);
			}
		/*	cout<<tmp<<endl;*/
		}
	}
	if(ans ==0){
		cout<<1<<endl;
	}else if(ans ==2 && s.length() ==2){
		cout<<1<<endl;

	}else if(ans ==s.length()){
		cout<<ans-2<<endl;
	}else{
		cout<<ans<<endl;
	}

	return 0;
}