Caps Lock Key Changes

Ignoring case, count how many times the letter changes between adjacent typed characters.

This site's standard input/output is stated explicitly.

输入格式

One line containing a string of English letters, of length 1..1000 (this site inputs the character sequence as a contiguous string of ASCII English letters).

输出格式

Output one integer answer.

样例 1

输入：

WwaAbb

输出：

2

样例 2

输入：

wWaWa

输出：

3

样例 3

输入：

aAAa

输出：

0

样例说明

Example 1: w changes to a, and a changes to b, 2 times in total. Example 2: among w, w, a, w, a there are 3 changes. Example 3: every letter is a, so there are 0 changes.