#include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
using namespace std;

int main(){
	//cin.tie(0);
	//ios::sync_with_stdio(false);
	
	string s;
	cin>>s;
	int sl=s.size();
	int ans=1;
	rep(i,sl){
		int j=0;
		int a=1;
		while(1){
			j++;
			if(i-j>-1 && i+j<sl){
				if(s[i-j]==s[i+j]){
					a+=2;
				}
			}else{
				break;
			}
		}
		ans=max(ans,a);
		if(i==sl-1) continue;
		if(i+1>=sl)continue;
		j=-1;
		a=0;
		while(1){
			j++;
			if(i-j>-1 && i+j+1<sl){
				if(s[i-j]==s[i+j+1]){
					a+=2;
				}
			}else{
				break;
			}
		}
		ans=max(ans,a);
	}
	cout<<ans<<endl;
}