def palim(string):
    a = string[::-1]
    if string == a:
        return False
    else:
        return True
string =input()
flag=0
for i in range(len (string)) :
    stringt=string[:i] + string[(i+1):]
    if palim(stringt)==False:
        print(i+1)
        flag=1
        break
if flag==0:
    print(0)