import sys

for line in sys.stdin:
    s1=line.strip()
    
    len1=len(s1)
    
    result=[]
    for i in range(len1):
        for j in range(len1, 0, -1):
            if s1[i:j]==s1[i:j][::-1]:
                result.append(j-i)
    print(max(result))