s = input(); n = len(s)
rl = [[] for _ in range(n)]
for i in range(n):
    for j in range(i,n):
        f = True
        for k in range((j-i+1)//2):
            if s[i+k]!=s[j-k]: f = False
        if f: rl[j].append(i-1)
dp = [0]*n+[n]
for r in range(n):
    for l in rl[r]: dp[r] = max(dp[r],min(dp[l],r-l))
print(dp[n-1])