#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=(b-1);i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

int main() {
  ll mx = 0;
  string s;
  cin>>s;
  ll length = s.sz;
  string s1;
  rep(i,0,2000){
    s1 += "*";
  }
  s = s1 + s + s1;
  rep(i,1500,s.sz-1500){
    ll c = 0;
    rep(j,0,1200){
      if(s[i+j]!=s[i-j]){
        if(s[i+j]=='*'||s[i-j]=='*'){
          c++;
        }
        else{
          c+=2;
        }
      }
    }
    mx = max(mx,length-c);
  }
  rep(i,1500,s.sz-1500){
    ll c = 0;
    rep(j,0,1200){
      if(s[i+1+j]!=s[i-j]){
        if(s[i+1+j]=='*'||s[i-j]=='*'){
          c++;
        }
        else{
          c+=2;
        }
      }
    }
    mx = max(mx,length-c);
  }
  cout << mx << endl;
	return 0;
}