//#define poj
#define zcz
#ifdef poj
//C++
#include<iomanip>
#include<iostream>
//C
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
//STL
#include<algorithm>
#include<bitset>
#include<functional>
#include<map>
#include<queue>
//#include<random>
#include<set>
#include<stack>
#include<string>
#include<vector>
#else
//#include<bits/stdc++.h>
#include<cstdio>
#include<cstring>
#include<algorithm>
#endif
using namespace std;
#ifdef zcz
class fastin{
	private:
#ifdef poj
	static const int MAXBF=1<<20;
#else
	const int MAXBF=1<<27;
#endif
	FILE *inf;
	char *inbuf,*inst,*ined;
	inline char _getchar(){
		if(inst==ined)inst=inbuf,ined=inbuf+fread(inbuf,1,MAXBF,inf);
		return inst==ined?EOF:*inst++;
	}
	public:
	fastin(FILE*_inf=stdin){
		inbuf=new char[MAXBF],inf=_inf,inst=inbuf,ined=inbuf;
	}
	~fastin(){delete inbuf;}
	template<typename Int> fastin&operator>>(Int &n){
		static char c;
		Int t=1;
		while((c=_getchar())<'0'||c>'9')if(c=='-')t=-1;
		n=(c^48);
		while((c=_getchar())>='0'&&c<='9')n=(n<<3)+(n<<1)+(c^48);
		n*=t;
		return *this;
	}
	fastin&operator>>(char*s){
		int t=0;
		static char c;
		while((c=_getchar())!=' '&&c!='\n')s[t++]=c;
		s[t]='\0';
		return *this;
	}
}fi;
class fastout{
	private:
#ifdef poj
	static const int MAXBF=1<<20;
#else
	const int MAXBF=1<<27;
#endif
	FILE *ouf;
	char *oubuf,*oust,*oued;
	inline void _flush(){fwrite(oubuf,1,oued-oust,ouf);}
	inline void _putchar(char c){
		if(oued==oust+MAXBF)_flush(),oued=oubuf;
		*oued++=c;
	}
	public:
	fastout(FILE*_ouf=stdout){
		oubuf=new char[MAXBF],ouf=_ouf,oust=oubuf,oued=oubuf;
	}
	~fastout(){_flush();delete oubuf;}
	template<typename Int> fastout&operator<<(Int n){
		if(n<0)_putchar('-'),n=-n;
		static char S[20];
		int t=0;
		do{S[t++]='0'+n%10,n/=10;}while(n);
		for(int i=0;i<t;++i)_putchar(S[t-i-1]);
		return *this;
	}
	fastout&operator<<(char c){_putchar(c);return *this;}
	fastout&operator<<(char*s){
		for(int i=0;s[i];++i)_putchar(s[i]);
		return *this;
	}
	fastout&operator<<(const char*s){
		for(int i=0;s[i];++i)_putchar(s[i]);
		return *this;
	}
}fo;
#define cin fi
#define cout fo
#else
#define czc ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#endif
#define mod 1000000007
#define ll unsigned long long
#define isinf 0x3f3f3f3f
#define ilinf 0x7fffffff
#define lsinf 0x3f3f3f3f3f3f3f3f
#define llinf 0x7fffffffffffffff
#define pii pair<int,int>
#define next ___
int n,len[2000010],mid,mx,ans;char s[2000010];
int solve(){
	n=strlen(s+1);ans=0;
	for(int i=n;i>=1;--i){
		s[2*i]=s[i];
		s[2*i+1]='#';
	}
	s[0]='*';s[1]='#';len[1]=mid=mx=1;
	for(int i=2;i<=2*n+1;++i){
		if(i<=mx)len[i]=min(len[mid*2-i],mx-i);
		while(s[i-len[i]]==s[i+len[i]])++len[i];
		if(i+len[i]>mx)mid=i,mx=i+len[i];
	}
	for(int i=1;i<=2*n+1;++i)ans=max(ans,len[i]-1);
	return ans;
}
int main(){
	#ifndef zcz
	czc;
	#endif
	int t=1;
	while(t--){
		cin>>(s+1);
		cout<<solve()<<'\n';
	}
	return 0;
}