#include<iostream>
#include<cstdio>
#include<vector>
#include<map>
#include<tuple>
#include<string>
#include<sstream>
#include<cmath>
#include<climits>
#include<algorithm>
#include<bitset>
#include<set>
#include<stack>
using namespace std;  
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
#define rep(i,n) for(ll i=0;i<(n);i++)  
#define tii tuple<int,int>
#define tiii tuple<int,int,int>
#define mt make_tuple
#define pb push_back  
#define ALL(a) (a).begin(),(a).end()
#define FST first
#define SEC second  
const int INF = (INT_MAX/2);
const ll LLINF = (LLONG_MAX/2);
const double eps = 1e-5;
const double PI = M_PI;  
#define DEB cerr<<"!"<<endl
#define SHOW(a,b) cerr<<(a)<<" "<<(b)<<endl
#define SHOWARRAY(ar,i,j) REP(a,i)REP(b,j)cerr<<ar[a][b]<<((b==j-1)?((a==i-1)?("\n\n"):("\n")):(" "))
#define DIV 1000000007
ll pow(ll x,ll n,ll m){ll r=1;while(n>0){if((n&1)==1)r=r*x%m;x=x*x%m;n>>=1;}return r%m;}
string ss;
int check(string s){
  rep(i,s.size()/2){
    if(s[i] != s[s.size()-1-i])
      return 0;
  }
  if(s.size() == ss.size())
    return s.size()-2;
  //SHOW(s,s.size());
  return s.size();
}
int main(){
   cin >> ss;
  int ans = 0;
  rep(i,ss.size())
    for(int j=0;i+j <= ss.size(); j++)
      ans = max(ans,check(ss.substr(i,j)));
  cout << ans << endl;
}