S = input()
n = len(S)
pal = [[0]*(n+1) for i in range(n+1)]


for i in range(n):
    l = i
    r = i
    while l >= 0 and r < n and S[l] == S[r]:
        pal[l][r+1] = 1
        l -= 1
        r += 1

    l = i
    r = i+1
    
    while l >= 0 and r < n and S[l] == S[r]:
        pal[l][r+1] = 1
        l -= 1
        r += 1

dp = [-1]*(n+1)
dp[0] = n+1
for i in range(n):
    if dp[i] == -1:
        continue
    for j in range(i+1,n+1):
        if pal[i][j]:
            dp[j] = max(dp[j],min(dp[i],j-i))
print(dp[-1])