Count Characters Before Uppercase

Consider only the text strictly before the first uppercase English letter, and count the distinct lowercase English letters in it; if there is no uppercase letter, consider the whole text. Under this definition, the original site's example aaAbcCABBc should give 1; this site has corrected it.

输入格式

This site's input: one line of printable ASCII text of length 0..100000, which may contain spaces; only A..Z and a..z count as letters.

输出格式

Output a single integer, the answer.

样例 1

输入：

aaAbcCABBc

输出：

1

样例 2

输入：

abca

输出：

3

样例 3

输入：

XYZ

输出：

0

样例说明

Example 1: only aa comes before the first uppercase A, and its only distinct lowercase letter is a; the answer is 1.

Example 2: there is no uppercase letter, and the distinct lowercase letters in the whole text are a, b, c; the answer is 3.

Example 3: the first character is already uppercase, so the prefix is empty; the answer is 0.