import sys

sys.setrecursionlimit(10**6)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.buffer.readline())
def MI(): return map(int, sys.stdin.buffer.readline().split())
def MI1(): return map(int1, sys.stdin.buffer.readline().split())
def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
def LI1(): return list(map(int1, sys.stdin.buffer.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def BI(): return sys.stdin.buffer.readline().rstrip()
def SI(): return sys.stdin.buffer.readline().rstrip().decode()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [[(-1, 0), (1, 0)], [(0, -1), (0, 1)]]
inf = 10**16
# md = 998244353
# md = 10**9+7
md = 10**8+7

def nCr(com_n, com_r):
    if com_n < com_r: return 0
    return fac[com_n]*ifac[com_r]%md*ifac[com_n-com_r]%md

# 準備
n_max = 200005
fac = [1]
for i in range(1, n_max+1): fac.append(fac[-1]*i%md)
ifac = [1]*(n_max+1)
ifac[n_max] = pow(fac[n_max], md-2, md)
for i in range(n_max-1, 1, -1): ifac[i] = ifac[i+1]*(i+1)%md

s = BI()
n = len(s)
ans = -1
for i in range(n):
    l, r = i-1, i+1
    d = 0
    while l >= 0 and r < n:
        if s[l] != s[r]: d += 2
        l, r = l-1, r+1
    cur = r-l-1-d
    if cur > ans: ans = cur

for i in range(1, n):
    l, r = i-1, i
    d = 0
    while l >= 0 and r < n:
        if s[l] != s[r]: d += 2
        l, r = l-1, r+1
    cur = r-l-1-d
    if cur > ans: ans = cur

print(ans)