import java.util.Scanner;
import java.util.regex.Pattern;

/**
 * Created by Prateek on 11/2/2017.
 */
public class One {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String s = sc.next();
        Pattern pnum = Pattern.compile("[\\d]");
        Pattern pa = Pattern.compile("[a-z]");
        Pattern pA = Pattern.compile("[A-Z]");
        Pattern ps = Pattern.compile("[^A-Za-z0-9]");
        int count=0;
        if(pnum.matcher(s).find()==false){
            count++;
        }
        if(pa.matcher(s).find()==false){
            count++;
        }
        if(pA.matcher(s).find()==false){
            count++;
        }
        if(ps.matcher(s).find()==false){
            count++;
        }
        if(s.length()+count<6){
            int diff = 6-count-s.length();
            count+=diff;
        }
        System.out.println(count);
    }
}