\begin{array}{c} \color{#FFFFFFff}{F}\color{#D0E4FFff}{u}\color{#A4C8FFff}{r}\color{#78ACFFff}{i}\color{#4C90FFff}{n}\color{#2064FFff}{a} \color{#0040A4ff}{F}\color{#2064FFff}{o}\color{#4C90FFff}{r}\color{#78ACFFff}{c}\color{#A4C8FFff}{a}\color{#D0E4FFff}{l}\color{#FFFFFFff}{o}\color{#D0E4FFff}{s} \end{array}

/** 
    * author: furinaforcalos 
    * created: 21.05.2025 
**/
#include <bits/stdc++.h>
#define hutao long long
using namespace std;
int main() 
{
	ios::sync_with_stdio(0); 
    cin.tie(0); 
    cout.tie(0);
    string s;
    cin>>s;
    hutao n=s.length();
	bool check=true;
    for(hutao i=1;i<n;i++) 
    {
        if(s[i]!=s[0]) 
        {
            check=false;
            break;
        }
    }
    if(check) 
    {
        cout<<0;
        return 0;
    }
    bool ok=true;
    for(hutao i=0;i<n/2;i++) 
    {
        if(s[i]!=s[n-1-i]) 
        {
            ok=false;
            break;
        }
    }
    if(!ok) 
    {
        cout<<n;
    }
    else 
    {
        cout<<n-1;
    }
}