CF279E Beautiful Decomposition

给定一个长度不超过 $10^6$ 的二进制数 $s$，求至少要用几个 $2^k$ 和 $-2^k(k\ge0)$ 加起来值等于 $n$。

仅一行包含字符串 $s(1\le|s|\le10^6)$。

输出一个整数表示最少的次数 by [@_I°Fear](https://www.luogu.com.cn/user/326452)

In the first sample $ n=2 $ is a beautiful number. In the second sample $ n=7 $ and Valera can decompose it into sum $ 2^{3}+(-2^{0}) $ . In the third sample $ n=109 $ can be decomposed into the sum of four summands as follows: $ 2^{7}+(-2^{4})+(-2^{2})+2^{0} $ .