import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
           Scanner sc=new Scanner(System.in);
           String res=sc.next();
           int first=0;
           int last=res.length()-1;
           int max_length=0;
           for(int i=0;i<res.length();i++){
               if(res.charAt(last)!=res.charAt(i)){
                   max_length=Math.max(max_length,last-i);
                   break;
               }
               last--;
           }
        for(int i=res.length()-1;i>=0;i--){
               if(res.charAt(first)!=res.charAt(i)){
                   max_length=Math.max(max_length,i-first);
                   break;
               }
               first++;
           }
        System.out.println(max_length);
    }
}