def sequence(s): left = 0 right = 1 length = [] mid = 0 while right < len(s) and left < right: if ord(s[right]) - ord(s[left]) == 1 or ord(s[right]) - ord(s[left]) == 0: right += 1 left += 1 else: length.append(right - mid) right = right + 1 left = left + 1 mid = left return max(length) s = input() print(sequence(s))