#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <climits>
#include <vector>
#include <numeric>
#include <complex>
#include <map>
#include <bitset>
#include <stack>
#include <queue>
using namespace std;

//#define __int64 long long
#define long __int64
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
const int Vecy[4] = {0,-1,0,1};
const int Vecx[4] = {1,0,-1,0};
const int modd = 1000000007;

bool check(string s){
	for(int i=1; i<s.length(); i++){
		if(s[0] != s[i]){
			return false;
		}
	}
	
	return true;
}

int main(){
	string s;
	int ans = 0;
	int l,r;
	cin >> s;
	
	for(int left=0; left<s.length(); left++){
		for(int right=left; right<s.length(); right++){
			l = left;
			r = right;
			while(l < r && s[l] == s[r]){
				l ++;
				r --;
			}
			
			if(l >= r){
				ans = max(ans, right - left + 1);
			}
		}
	}
	
	if(ans == s.length()){
		if(check(s)){
			cout << ans - 1 << endl;
		}else{
			cout << ans - 2 << endl;
		}
	}else{
		cout << ans << endl;
	}
	
    return 0;
}