#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
string s;
int sa[400002], lcp[400002], rk[400002];
int tmp[400002];
int n, k;
bool compare_sa(int i, int j){
  if(rk[i]!=rk[j]) return rk[i]<rk[j];
  else{
    int ri, rj;
    if(i+k<=n) ri=rk[i+k];
    else ri=-1;
    if(j+k<=n) rj=rk[j+k];
    else rj=-1;
    return ri<rj;
  }
}
void construct_sa(string s, int *sa){
  n=s.size();
  for(int i=0; i<=n; i++){
    sa[i]=i;
    if(i<n){
      rk[i]=s[i]-'a';
    }else{
      rk[i]=-1;
    }
  }
  for(k=1; k<=n; k*=2){
    sort(sa, sa+n+1, compare_sa);
    tmp[sa[0]]=0;
    for(int i=1; i<=n; i++){
      tmp[sa[i]]=tmp[sa[i-1]];
      if(compare_sa(sa[i-1], sa[i])) tmp[sa[i]]++;
    }
    for(int i=0; i<=n; i++) rk[i]=tmp[i];
  }
}
void construct_lcp(string s, int *sa, int *lcp){
	int n=s.size();
	for(int i=0; i<n; i++) rk[sa[i]]=i;
	int h=0;
	lcp[0]=0;
	for(int i=0; i<n; i++){
		int j=sa[rk[i]-1];
		if(h>0) h--;
		for(; j+h<n && i+h<n; h++){
			if(s[j+h]!=s[i+h]) break;
		}
		lcp[rk[i]-1]=h;
	}
}
const int MAX_N=1<<19;
const int INF=1e9;
int m0, mn[2*MAX_N];
void init(int m_){
	m0=1;
	while(m0<m_) m0<<=1;
	for(int i=0; i<m_; i++){
		mn[m0+i]=lcp[i];
	}
	for(int i=m_+m0; i<=2*m0-1; i++) mn[i]=INF;
	for(int i=m0-1; i>=1; i--){
		mn[i]=min(mn[2*i], mn[2*i+1]);
	}
}
int query(int a, int b){
	a+=m0, b+=m0;
	int ans=INF;
	for(;a<b; a>>=1, b>>=1){
		if(b&1) ans=min(ans, mn[--b]);
		if(a&1) ans=min(ans, mn[a++]);
	}
	return ans;
}
int main()
{
	cin>>s;
	int m=s.size();
	string t=s;
	reverse(t.begin(), t.end());
	s+='$'+t;
	construct_sa(s, sa);
	construct_lcp(s, sa, lcp);
	for(int i=0; i<=s.size(); i++) rk[sa[i]]=i;
	init(s.size()+1);
	int ans=0;
	for(int i=0; i<m; i++){
		int j=2*m-i;
		int l=query(min(rk[i], rk[j]), max(rk[i], rk[j]));
		if(i-l>=0 || i+l<=m-1) ans=max(ans, 2*l-1);
		else ans=max(ans, m-2);
		if(i-l>0 && s[i-l-1]==s[i+l]){
			int j1=2*m-(i-l-1);
			int l1=query(min(rk[j1], rk[i+l]), max(rk[i+l], rk[j1]));
			ans=max(ans, 2*l-1+2*l1);
		}
		if(i+l<m-1 && s[i-l]==s[i+l+1]){
			int j1=2*m-(i-l);
			int l1=query(min(rk[i+l+1], rk[j1]), max(rk[i+l+1], rk[j1]));
			ans=max(ans, 2*l-1+2*l1);
		}
		if(i-l>=0 && i+l-1<=m-1 && s[i-l]==s[i+l-1]){
			int j1=2*m-(i-l);
			int l1=query(min(rk[i+l-1], rk[j1]), max(rk[i+l-1], rk[j1]));
			ans=max(ans, 2*l-3+2*l1);
		}
		if(i-l+1>=0 && i+l<=m-1 && s[i-l+1]==s[i+l]){
			int j1=2*m-(i-l+1);
			int l1=query(min(rk[i+l], rk[j1]), max(rk[i+l], rk[j1]));
			ans=max(ans, 2*l-3+2*l1);
		}
	}
	for(int i=1; i<m; i++){
		int j=2*m-i+1;
		int l;
		if(s[i-1]!=s[i]){
			l=0;
		}else{
			l=query(min(rk[i], rk[j]), max(rk[i], rk[j]));
		}
		if(i-1-l>=0 || i+l<=m-1) ans=max(ans, 2*l);
		else ans=max(ans, m-2);
		if(i-l-1>0 && s[i-l-2]==s[i+l]){
			int j1=2*m-(i-l-2);
			int l1=query(min(rk[j1], rk[i+l]), max(rk[i+l], rk[j1]));
			ans=max(ans, 2*l+2*l1);
		}
		if(i+l<m-1 && s[i-l-1]==s[i+l]){
			int j1=2*m-(i-l-1);
			int l1=query(min(rk[i+l+1], rk[j1]), max(rk[i+l+1], rk[j1]));
			ans=max(ans, 2*l+2*l1);
		}
		if(i-1-l>=0 && i+l-1<=m-1 && s[i-l-1]==s[i+l-1]){
			int j1=2*m-(i-l-1);
			int l1=query(min(rk[i+l-1], rk[j1]), max(rk[i+l-1], rk[j1]));
			ans=max(ans, 2*l-2+2*l1);
		}
		if(i-l>=0 && i+l<=m-1 && s[i-l]==s[i+l]){
			int j1=2*m-(i-l-1);
			int l1=query(min(rk[i+l], rk[j1]), max(rk[i+l], rk[j1]));
			ans=max(ans, 2*l-2+2*l1);
		}
	}
	cout<<ans<<endl;
	return 0;
}