101242: [AtCoder]ABC124 C - Coloring Colorfully

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

Score : $300$ points

Problem Statement

$N$ tiles are arranged in a row from left to right. The initial color of each tile is represented by a string $S$ of length $N$.

The $i$-th tile from the left is painted black if the $i$-th character of $S$ is 0, and painted white if that character is 1.

You want to repaint some of the tiles black or white, so that any two adjacent tiles have different colors.

At least how many tiles need to be repainted to satisfy the condition?

Constraints

  • $1 \leq |S| \leq 10^5$
  • $S_i$ is 0 or 1.

Input

Input is given from Standard Input in the following format:

$S$

Output

Print the minimum number of tiles that need to be repainted to satisfy the condition.


Sample Input 1

000

Sample Output 1

1

The condition can be satisfied by repainting the middle tile white.


Sample Input 2

10010010

Sample Output 2

3

Sample Input 3

0

Sample Output 3

0

Input

题意翻译

$N$ 个磁贴从左到右连续排列。 每个图块的初始颜色由长度为 $N$ 的字符串 $S$ 表示。 如果 $S$ 的第 $i$ 个字符为 `0`,则从左边开始的第 $i$ 个图块被涂成黑色,如果该字符是 `1`,则涂成白色。 您想将某些图块重新涂成黑色或白色,以便任何两个相邻的图块具有不同的颜色。 至少需要重新粉刷多少瓷砖才能满足条件?

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