#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using pi=pair<int,int>;
#define rng(i,a,b) for(int i=(int)a;i<(int)b;i++)
#define rep(i,n) rng(i,0,n)
#define repn(i,n) rng(i,1,n+1)
#define eb emplace_back
#define pb push_back
#define mp make_pair
#define a first
#define b second
template<class t>using vc=vector<t>;
using vi=vc<int>;
template<class S>vi manacher(const S&s){
	int n=s.size();
	vi v(n);
	int j=0;
	rep(i,n){
		int k=j*2-i;
		if(k>=0&&i+v[k]<j+v[j])
			v[i]=v[k];
		else{
			v[i]=j+v[j]-i;
			j=i;
			while(i+v[i]<n&&i-v[i]>=0&&s[i-v[i]]==s[i+v[i]])
				v[i]++;
		}
	}
	return v;
}
void slv(){
	string str2;cin >> str2;
	int n=str2.size();
	string str="";
	rep(i, str2.size()){
		str.pb(str2[i]);
		if(i==str2.size()-1)break;
		str.pb('$');
	}
	auto mc = manacher(str);
	vc<int>len(n-1);
	rep(i, n-1) len[i] = mc[i*2+1] / 2;
	//rep(i, n-1) cout << len[i] << ' '; cout << endl;
	int lb=0, ub=n-2;
	int L=0,R=n-1;
	while(1){
		bool upd = false;
		//cout << L << " " << R << endl;
		while(lb <= ub){
			if(len[lb] >= min(lb-L+1, R-lb)){
				R=max(R,2*lb+1-L);
				L=lb+1;
				lb=L, ub=R-1;
				upd=true;
				break;
			}
			else lb++;
			
			if(len[ub] >= min(ub-L+1, R-ub)){
				L=min(L, 2*ub+1-R);
				R=ub;
				lb=L, ub=R-1;
				upd=true;
				break;
			}
			else ub--;
		}
		if(!upd) break;
	}
	cout << R-L+1 << endl;
}
signed main(){
	ios::sync_with_stdio(0);
	cout<<fixed<<setprecision(20);
	slv();
}