import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String p) {
        boolean d = false;
        boolean u = false;
        boolean l = false;
        boolean q = false;
        String s = "!@#$%^&*()-+";
        String num = "0123456789";
        String lower = "abcdefghijklmnopqrstuvwxyz";
        String upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        for(int i=0; i<p.length(); i++){
            if(!d && num.contains(""+p.charAt(i))){
                d = true;
            }
            if(!l && lower.contains(""+p.charAt(i))){
                l = true;
            }
            if(!u && upper.contains(""+p.charAt(i))){
                u = true;
            }
            if(!q && s.contains(""+p.charAt(i))){
                q = true;
            }
        }
        int a = 0;
        if(!d)
            a++;
        if(!l)
            a++;
        if(!u)
            a++;
        if(!q)
            a++;
        if(p.length()+a<6){
            a = 6-p.length();
        }
        return a;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}