#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=4010000;
typedef pair<int,int> hashv;
const ll mod1=1000000007;
const ll mod2=1000000009;

hashv operator + (hashv a,hashv b) {
	int c1=a.fi+b.fi,c2=a.se+b.se;
	if (c1>=mod1) c1-=mod1;
	if (c2>=mod2) c2-=mod2;
	return mp(c1,c2);
}

hashv operator - (hashv a,hashv b) {
	int c1=a.fi-b.fi,c2=a.se-b.se;
	if (c1<0) c1+=mod1;
	if (c2<0) c2+=mod2;
	return mp(c1,c2);
}

hashv operator * (hashv a,hashv b) {
	return mp(1ll*a.fi*b.fi%mod1,1ll*a.se*b.se%mod2);
}
hashv base,pw[N],hs1[N],hs2[N];
char s[N];
bool L[N];
int mv[N];
int main() {
	scanf("%s",s);
	int n=strlen(s);
	int ans=n;
	base=mp(rnd(11111111)+1111111,rnd(111111)+11111111);
	pw[0]=mp(1,1);
	rep(i,1,n+1) pw[i]=pw[i-1]*base;
	rep(i,0,n) hs1[i+1]=hs1[i]*base+mp(s[i],s[i]);
	hs2[n]=mp(0,0);
	per(i,0,n) hs2[i]=hs2[i+1]*base+mp(s[i],s[i]);
	auto ispal=[&](int l,int r) {
		return hs1[r+1]-hs1[l]*pw[r-l+1]==hs2[l]-hs2[r+1]*pw[r-l+1];
	};
	int lst=0;
	L[0]=1;
	rep(i,0,n) {
		if (2*i+1-lst<n&&ispal(lst,2*i+1-lst)) {
			lst=i+1;
			L[lst]=1;
			//printf("L %d\n",i+1);
		}
	}
	rep(i,0,n+1) if (L[i]) mv[i]=i; else mv[i]=mv[i-1];
	lst=n-1;
	ans=min(ans,n-mv[n-1]);
	per(i,0,n) {
		if (2*i-1-lst>=0&&ispal(2*i-1-lst,lst)) {
			lst=i-1;
			ans=min(ans,i-mv[i-1]);
			//printf("R %d %d\n",i,mv[i-1]);
		}		
	}
	printf("%d\n",ans);
}