Unique Characters Count

You are given a string S. Your task is to calculate the number of unique characters present in the string. In other words, you need to compute \(\left|\{ c : c \in S \}\right|\), which is the size of the set of characters from S.

Example:

If S = "hello", the unique characters are {h, e, l, o}, so the answer is 4.

inputFormat

Input consists of a single line containing the string (S). The string may include letters, digits, and various symbols. It is guaranteed that the input line is non-empty.

outputFormat

Output a single integer denoting the number of unique characters in the string S.## sample

hello

4