/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		SortedSet <Character> set = new TreeSet<>();
		Scanner in = new Scanner(System.in);
		String s = in.next();
		for(int i = 0; i < s.length(); i++){
        	set.add(s.charAt(i));
		}
		System.out.print(set.size());
	}
}
 

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

cXdlcnR5

qwerty