You just discovered strings in C++. You are so desperate with strings that you continue to solve strings related questions for 10 straight hours without any break. You decided to solve questions of relatively higher level. It is when you came across the following question.

Find the number of different characters in a given string given that characters in string are present in domain [A,Z] && [a,z]

Solve the given question without taking anyone's help. So that you can SIP (sleep in peace).

INPUT FORMAT :
First and only line of input will contain a string S.

OUTPUT FORMAT :
Your output should contain 1 line, printing total number of different characters in S.

CONSTRAINTS :
1≤ length of S ≤10³