import java.util.*;

public class Exercise85{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    String s = sc.next();
    char[] sArray = s.toCharArray();

    int answer = 0;

    for(int i = 0; i < sArray.length; i++){
      for(int j = sArray.length - 1; j >= i; j--){
        if(sArray[i] == sArray[j]){
          char[] kArray = Arrays.copyOfRange(sArray, i, j + 1);
          if(kArray.length == sArray.length){
            continue;
          }
          char[] kArrayD = new char[kArray.length];
          for(int k = 0; k < kArray.length; k++){
            kArrayD[k] = kArray[kArray.length - 1 - k];
          }
          System.out.println(Arrays.toString(kArray));
          if(Arrays.equals(kArray, kArrayD)){
            answer = Math.max(answer, kArray.length);
          }
        }
      }
    }
    System.out.println(answer);
  }
}