def huiwen(b):
    if b==b[::-1]:
        return 1
    else:
        return 0
str1=input()
while(huiwen(str1)):
    b=len(str1)
    str1=str1[0:int(b//2)]
print(len(str1))


/**************************************************************
	Problem: 1134
	User: admin
	Language: Python
	Result: Accepted
	Time:89 ms
	Memory:34244 kb
****************************************************************/