import sys s = input() def center(l, r): while l >= 0 and r < len(s) and s[l] == s[r]: l -= 1 r += 1 return r - l - 1 result = 1 for i in range(len(s)): l1 = center(i, i) l2 = center(i, i+1) result = max(result, max(l1, l2)) print(result)