import sys
input = sys.stdin.readline

S=list(input().strip())

# Manacher
# https://snuke.hatenablog.com/entry/2014/12/02/235837

T=[]
for s in S:
    T.append(s)
    T.append("0")

LEN=len(T)
i=0
j=0
R=[0]*LEN # 文字 i を中心とする最長の回文の半径

while i<LEN:
    while i-j>=0 and i+j<LEN and T[i-j]==T[i+j]:
        j+=1
    R[i]=j
    
    k=1
    while i-k>=0 and i+k<LEN and k+R[i-k]<j:
        R[i+k]=R[i-k]
        k+=1

    i+=k
    j-=k

def pali(x,y):
    l=2*x
    r=2*y
    mid=(l+r)//2
    if R[mid]>=mid-l+1:
        return True
    else:
        return False
    


DP=[0]*(len(S)+1)
DP[0]=1<<60
for i in range(len(S)):
    for j in range(i,len(S)):
        if pali(i,j)==True:
            DP[j+1]=max(DP[j+1],min(DP[i],j+1-i))

print(DP[-1])