S=input()
ok=[[False for _ in range(len(S))] for _ in range(len(S))]
for i in range(len(S)):
    for j in range(i,len(S)):
        Len=(j-i+1)//2
        s=S[i:j+1]
        if S[i:j+1]==s[::-1]:
            ok[i][j]=True

def okey(mid):
    dp=[False for _ in range(len(S)+1)]
    dp[len(S)]=True
    for i in range(len(S)):
        if dp[i-1]:
            for d in range(mid-1,len(S)-i):
                if ok[i][i+d]:
                    dp[i+d]=True
    if dp[len(S)-1]:
        return True
    return False

left,right=1,len(S)
while right-left>1:
    mid=(left+right)//2
    if okey(mid):
        left=mid
    else:
        right=mid
print(left)