import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String read = br.readLine();
        int brojac = 0;
        for(int i=0;i<read.length();i++) {
            if(Character.isLetter(read.charAt(i))) {
                brojac++;
            }
        }
        System.out.println(brojac);
    }
}