#include<bits/stdc++.h>
using namespace std;
 
using ll=long long;
using pp=pair<int,int>;
#define sr string 
#define vc vector
#define db double
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define pque priority_queue
#define bpc(a) __builtin_popcount(a)
int main(){
	sr s;cin>>s;
	int n=s.size();
	vc ok(n,vc<int>(n,false));
	rep(i,n){
		int l=i,r=i;
		while(l>=0&&r<n&&s[l]==s[r]){
			ok[l][r]=true;
			l--,r++;
		}
	}
	rep(i,n-1){
		int l=i,r=i+1;
		while(l>=0&&r<n&&s[l]==s[r]){
			ok[l][r]=true;
			l--,r++;
		}
	}
	vc<int>dp(n+1,0);
	dp[0]=1e9;
	rep(i,n)for(int j=i+1;j<=n;j++)if(ok[i][j-1]){
		int d=j-i;
		dp[j]=max(dp[j],min(dp[i],d));
	}
	cout<<dp[n];
}