s = input().strip()
n = len(s)

# Precompute palindrome table
pal = [[False] * n for _ in range(n)]
for i in range(n-1, -1, -1):
    for j in range(i, n):
        if i == j:
            pal[i][j] = True
        elif i + 1 == j:
            pal[i][j] = (s[i] == s[j])
        else:
            pal[i][j] = (s[i] == s[j] and pal[i+1][j-1])

low = 1
high = n
max_x = 0

while low <= high:
    mid = (low + high) // 2
    dp = [False] * (n + 1)
    dp[0] = True  # empty prefix

    for i in range(1, n + 1):
        end_j = i - mid
        if end_j >= 0:
            found = False
            for j in range(end_j, -1, -1):
                if dp[j] and pal[j][i-1]:
                    dp[i] = True
                    found = True
                    break
            # If found, dp[i] is True; else remains False
    
    if dp[n]:
        max_x = mid
        low = mid + 1
    else:
        high = mid - 1

print(max_x)