import java.util.Scanner;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
// 注意 hasNext 和 hasNextLine 的区别
//while (in.hasNextInt()) { // 注意 while 处理多个 case
while (in.hasNext()) { // 注意 while 处理多个 case
//int a = in.nextInt();
//int b = in.nextInt();
//System.out.println(a + b);
String a = in.next();
int maxLength=0;
for(int i=0;i<a.length();i++){
for(int j=a.length();j>0;j--){
String b = a.substring(i,j);
StringBuilder sb = new StringBuilder(b);
String c = sb.reverse().toString();
if(b.equals(c)){
if(maxLength<b.length()){
maxLength=b.length();
}
break;
}
}
}
System.out.print(maxLength);
}
}
}