#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define watch(a) { std::cout << #a << " = " << a << "\n"; }
template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }
template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }
template<class T, class V> istream& operator>> (istream& ist, pair<T, V>& p) { return ist >> p.first >> p.second; }
template<class T> ostream& operator<< (ostream& ost, pair<T, T>& p) { return ost << p.first << ", " << p.second; }
template<class T> istream& operator>> (istream& ist, vector<T>& vs) { for(auto& e: vs) ist >> e; return ist; }

typedef long long ll;
int const inf = INT_MAX / 2;

string S;

bool is_palindrome(int begin, int end) {
  rep(i, end - begin) {
    if (S[begin + i] != S[end - 1 - i]) {
      return false;
    }
  }
  return true;
}

int main() {
  cin >> S;
  int N = S.size();
  int ans = 0;
  rep(st, N) {
    REP(len, 1, N) {
      if (st + len > N) break;
      if (is_palindrome(st, st + len)) {
        ans = max(ans, len);
      }
    }
  }
  cout << ans << endl;
}