#pragma region template
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
 
using ll=long long;
using ld=long double;
using vi=vector<int>;
using vll=vector<ll>;
using pi=pair<int,int>;
using pll=pair<ll,ll>;
 
#define overload2(a,b,c,...) c
#define overload3(a,b,c,d,...) d
#define overload4(a,b,c,d,e,...) e
#define overload5(a,b,c,d,e,f,...) f
 
#define TYPE1(T) template<typename T>
#define TYPE2(T,U) template<typename T,typename U>
#define TYPE(...) overload2(__VA_ARGS__,TYPE2,TYPE1)(__VA_ARGS__)
#define TYPES1(T) template<typename... T>
#define TYPES2(H,T) template<typename H,typename... T>
#define TYPES(...) overload2(__VA_ARGS__,TYPES2,TYPES1)(__VA_ARGS__)
 
#define REP4(i,s,n,d) for(int i=(s);i<(n);i+=(d))
#define REP3(i,s,n) REP4(i,s,n,1)
#define REP2(i,n) REP3(i,0,n)
#define REP1(n) REP2(tomato,n)
#define REP(...) overload4(__VA_ARGS__,REP4,REP3,REP2,REP1)(__VA_ARGS__)
 
#define RREP4(i,n,s,d) for(int i=(n)-1;i>=(s);i-=(d))
#define RREP3(i,n,s) RREP4(i,n,s,1)
#define RREP2(i,n) RREP3(i,n,0)
#define RREP1(n) RREP2(tomato,n)
#define RREP(...) overload4(__VA_ARGS__,RREP4,RREP3,RREP2,RREP1)(__VA_ARGS__)

#define FOR4(a,b,c,d,v) for(auto [a,b,c,d]:v)
#define FOR3(a,b,c,v) for(auto [a,b,c]:v)
#define FOR2(a,b,v) for(auto [a,b]:v)
#define FOR1(a,v) for(auto a:v)
#define FOR(...) overload5(__VA_ARGS__,FOR4,FOR3,FOR2,FOR1)(__VA_ARGS__)

#define AFOR4(a,b,c,d,v) for(auto&[a,b,c,d]:v)
#define AFOR3(a,b,c,v) for(auto&[a,b,c]:v)
#define AFOR2(a,b,v) for(auto&[a,b]:v)
#define AFOR1(a,v) for(auto&a:v)
#define AFOR(...) overload5(__VA_ARGS__,AFOR4,AFOR3,AFOR2,AFOR1)(__VA_ARGS__)

#define CFOR4(a,b,c,d,v) for(const auto&[a,b,c,d]:v)
#define CFOR3(a,b,c,v) for(const auto&[a,b,c]:v)
#define CFOR2(a,b,v) for(const auto&[a,b]:v)
#define CFOR1(a,v) for(const auto&a:v)
#define CFOR(...) overload5(__VA_ARGS__,CFOR4,CFOR3,CFOR2,CFOR1)(__VA_ARGS__)
 
#define ALL(v) v.begin(),v.end()
#define RALL(v) v.rbegin(),v.rend()
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort(RALL(v))
#define REVERSE(v) reverse(ALL(v))
#define UNIQUE(v) SORT(v),v.erase(unique(ALL(v)),v.end())
#define SZ(v) int(v.size())
 
TYPES(T) void input(T&... a){ (cin>>...>>a); }
#define DECLARE(T,...) T __VA_ARGS__;input(__VA_ARGS__);
#define INT(...) DECLARE(int,__VA_ARGS__)
#define STR(...) DECLARE(string,__VA_ARGS__)
#define LL(...) DECLARE(long long,__VA_ARGS__)
#define CHR(...) DECLARE(char,__VA_ARGS__)
#define DBL(...) DECLARE(double,__VA_ARGS__)
#define VI(n,v) vi v(n);cin>>v;
#define VLL(n,v) vll v(n);cin>>v;
 
TYPE(T) istream&operator>>(istream&is,vector<T>&v){
  for(auto&a:v)cin>>a;
  return is;
}
TYPE(T) ostream&operator<<(ostream&os,const vector<T>&v){
  if(&os==&cerr)os<<"[";
  REP(i,v.size()){
    os<<v[i];
    if(i+1<v.size())os<<(&os==&cerr?",":" ");
  }
  if(&os==&cerr)os<<"]";
  return os;
}
TYPE(T,S) istream&operator>>(istream&is,pair<T,S>&p){
  cin>>p.first>>p.second;
  return is;
}

#ifdef __DEBUG
 #include <debug>
#else
 #define debug(...) void(0)
#endif

void print(){ cout << '\n'; }
TYPES(T,Ts) void print(const T& a,const Ts&... b){
  cout<<a;
  (cout<<...<<(cout<< ' ',b));
  cout << '\n';
}
 
TYPE(T) using pq=priority_queue<T>;
TYPE(T) using pqg=priority_queue<T,vector<T>,greater<T>>;
TYPE(T) T pick(queue<T>& que){assert(que.size()); T a=que.front();que.pop();return a;}
TYPE(T) T pick(pq<T>& que){assert(que.size()); T a=que.top();que.pop();return a;}
TYPE(T) T pick(pqg<T>& que){assert(que.size()); T a=que.top();que.pop();return a;}
TYPE(T) T pick(stack<T>& sta){assert(sta.size()); T a=sta.top();sta.pop();return a;}
 
string YES(bool f=true){return (f?"YES":"NO");}
string Yes(bool f=true){return (f?"Yes":"No");}
string yes(bool f=true){return (f?"yes":"no");}
 
constexpr int INF=1e9+7;
constexpr ll LINF=ll(1e18)+7;
constexpr ld EPS=1e-10;
 
vi iota(int n){vi a(n);iota(ALL(a),0);return a;}
TYPE(T) vector<pair<T,int>> query_sort(const vector<T>&v){
  vector<pair<T,int>> res(v.size());
  REP(i,v.size())res[i]={v[i],i};
  SORT(res);
  return res;
}
TYPE(T) T rev(T a){ REVERSE(a);return a; }
TYPE(T) void fin(T a){cout<<a<<'\n';exit(0);}
TYPE(T) bool chmax(T &a,T b){return (a<b&&(a=b,true));}
TYPE(T) bool chmin(T &a,T b){return (a>b&&(a=b,true));}
TYPES(T,Ns) auto make_vector(T x,int n,Ns ...ns){
  if constexpr(sizeof...(ns)==0)return vector<T>(n,x);
  else return vector(n,make_vector<T>(x,ns...));
}
bool in(const ll S,const int a){return (S>>a)&1;}
int popcount(const ll S){return __builtin_popcountll(S);}
int digit(char c){ return (c>='0' and c<='9' ? c-'0' : -1);}
ll sqrtll(ll a){ 
  for(ll b=sqrt(a);b*b<=a;b++)if(b*b==a)return b;
  for(ll b=sqrt(a);b>=0 and b*b>=a;b--)if(b*b==a)return b;
  return -1;
}
#pragma endregion template

template<char MARGIN>
struct ForString{
  static constexpr char change(char c){ return c-MARGIN; }
  static constexpr char restore(char a){ return a+MARGIN; }

  static vector<char> change(const string&s){
    vector<char> v(s.size());
    for(int i=0;i<s.size();i++)v[i]=change(s[i]);
    return v;
  }
  static string restore(const vector<char>&v){
    string s(v.size(),'#');
    for(int i=0;i<v.size();i++)s[i]=restore(v[i]);
    return s;
  }
};
struct FSAa{
  static constexpr char change(char c){ return c<='Z'?c-'A':26+c-'a'; }
  static constexpr char restore(char a){ return a<26?'A':a-26+'a'; }
  static vector<char> change(const string&s){
    vector<char> v(s.size());
    for(int i=0;i<s.size();i++)v[i]=change(s[i]);
    return v;
  }
  static string restore(const vector<char>&v){
    string s(v.size(),'#');
    for(int i=0;i<v.size();i++)s[i]=restore(v[i]);
    return s;
  }
};
using FSA=ForString<'A'>;
using FSa=ForString<'a'>;
using FS0=ForString<'0'>;

#ifdef STR
  #define STRA(s) STR(s##tomato);auto s=FSA::change(s##tomato);
  #define STRa(s) STR(s##tomato);auto s=FSa::change(s##tomato);
  #define STR0(s) STR(s##tomato);auto s=FS0::change(s##tomato);
#endif
struct Modint61{
  using ll=long long;
  static constexpr ll MOD=(1LL<<61)-1;
  ll v;
  Modint61(const ll x=0):v(x){
    if(v<0||v>=MOD){
      v%=MOD;
      if(v<0)v+=MOD;
    }
  }
  static Modint61 raw(ll v){
    Modint61 x;
    x.v=v;
    return x;
  }
private:
  template<int d>
  static constexpr pair<ll,ll> divide(const ll&a){
    return {a>>d, a&((1LL<<d)-1)};
  }
public:
  Modint61 pow(long long k){
    Modint61 res(1),tmp(v);
    while(k){
      if(k&1)res*=tmp;
      tmp*=tmp;
      k>>=1;
    }
    return res;
  }

  Modint61 inv(){ return pow(MOD-2); }

  Modint61& operator+=(Modint61 a){v+=a.v;if(v>=MOD)v-=MOD;return *this;}
  Modint61& operator-=(Modint61 a){v+=MOD-a.v;if(v>=MOD)v-=MOD;return *this;}
  Modint61& operator*=(Modint61 a){
    const auto [vu,vd]=divide<31>(v);
    const auto [au,ad]=divide<31>(a.v);
    ll x = vd*au + vu*ad;
    const auto [xu,xd]=divide<30>(x);
    v = vu*au*2 + xu + (xd<<31) + vd*ad;
    if(v>=MOD){
      const auto [vu2,vd2]=divide<61>(v);
      v=vu2+vd2;
    }
    if(v>=MOD)v-=MOD;
    return *this;
  }
  Modint61& operator/=(Modint61 a){
    return (*this)*=a.inv();
  }
  Modint61 operator+(Modint61 a) const{return Modint61(v)+=a;}
  Modint61 operator-(Modint61 a) const{return Modint61(v)-=a;}
  Modint61 operator*(Modint61 a) const{return Modint61(v)*=a;}
  Modint61 operator/(Modint61 a) const{return Modint61(v)/=a;}

  Modint61 operator+() const{return *this;}
  Modint61 operator-() const{return v?Modint61(MOD-v):Modint61(v);}

  bool operator==(const Modint61 a)const{return v==a.v;}
  bool operator!=(const Modint61 a)const{return v!=a.v;}
  bool operator<(const Modint61 a)const{return v<a.v;}
};

random_device rollonghash_rnd;
mt19937 rollonghash_mt(rollonghash_rnd());

template<typename CHAR=char,typename MINT=Modint61>
class RollingHash{
  using ll=long long;
  static constexpr ll mod = (1LL<<61)-1;
  using T=ll;
  inline static const MINT base=MINT::raw(rollonghash_mt()%(mod-2)+2);

  

  int n;
  vector<MINT> hash,power;
public:
  RollingHash(const vector<CHAR>&v):n(v.size()),hash(n+1,0),power(n+1,1){
    for(int i=0;i<n;i++){
      hash[i+1]=nxt_hash(hash[i],v[i]);
      power[i+1]=power[i]*base;
    }
  }

  static MINT nxt_hash(MINT x,CHAR c){ return (x*base) + MINT::raw(c); }
  
  T get_hash(int l=0,int r=-1){
    if(r<0)r=n;
    return (hash[r]-hash[l]*power[r-l]).v;
  }
  
  static T full_hash(const vector<CHAR>&v){
    MINT res=0;
    for(const char&c:v)res=nxt_hash(res,c);
    return res.v;
  }
};

template<class F>
long long binary_search_ll(long long ok,long long ng,const F &is_ok){
  while(abs(ok-ng)>1){
    long long mid=(ok+ng)>>1;
    (is_ok(mid)?ok:ng)=mid;
  }
  return ok;
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  STRa(s);
  int n=s.size();
  RollingHash RH(s);
  auto t=rev(s);
  RollingHash RH2(t);

  auto is_pa=[&](int l,int r){
    return RH.get_hash(l,r)==RH2.get_hash(n-r,n-l);
  };

  if(is_pa(0,n))fin(n);

  vector<int> a(n+1,-1);
  a[0]=INF;
  REP(i,n){
    for(int j=i+1;j<=n;j++){
      if(is_pa(i,j)){
        chmax(a[j],min(a[i],j-i));
      }
    }
  }
  cout<<a[n]<<'\n';

  /*

  auto is_ok=[&](int x){
    vector<bool> used(n+1,false);//[0,i)が作れた
    used[0]=true;
    for(int i=0;i<n;i++){
      if(!used[i])continue;
      for(int j=i+x;j<=n;j++)if(is_pa(i,j))used[j]=true;
    }
    return used[n];
  };

  cout<<binary_search_ll(1,n,is_ok)<<'\n';*/
}