网易机器学习笔试code，橡皮长度

# -*- coding: utf-8 -*-
import sys
while 1:
    line = sys.stdin.readline().strip()
    if line:
        a = line
    else:
        break
n = len(a)
last = ''
while last != a:
    last = a
    for i in range(n-1):
        left = a[0]
        right = a[-1]
        if a[i] == a[i+1] and left != right:
            a = a[:i+1][::-1] + a[i+1:][::-1]
            break
count = 1
max = 1
for i in range(n-1):
    if a[i] != a[i+1]:
        count += 1
        if count > max:
            max = count
    else:
        count = 1
print max