#include <bits/stdc++.h>
#include <cmath>
#include <climits>
#include <cstdio>

using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define DEBUG(x) cout<<#x<<": "<<x<<endl

typedef pair<int,int> P;
typedef long long int LL;
typedef pair<LL,LL> LP;

bool check_Palindrome(string s);

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	string s;
	cin >> s;
	//cout << check_Palindrome(s) << endl;
	int n = SZ(s);
	int ans = -1;
	REP(i,n){
		REP(j,i+1){
			if(i == n-1 && j == 0)	continue;
			if(check_Palindrome(s.substr(j,i-j+1))){
				//DEBUG(i); DEBUG(j); cout << i-j+1 << endl << endl;
				ans = max(ans,i-j+1);
			}
		}
	}
	cout << ans << endl;
	return 0;
}

bool check_Palindrome(string s){
	bool res = true;
	for(int i = 0; i < SZ(s); i++){
		if(s[i] != s[SZ(s)-1-i]) res = false;
	}
	return res;
}