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 password) {
            boolean num=false;
        boolean lc=false;
        boolean uc=false;
        boolean sc=false;
        int c=0;
        for(int i=0;i<n;i++)
        {
            char ch=password.charAt(i);
            if(ch>='a' && ch<='z')
                lc=true;
            else if(ch>='A' && ch<='Z')
                uc=true;
            else if(ch>='0' && ch<='9')
                num=true;
            else
                sc=true;
        }
        if(lc==false)
            c++;
        if(uc==false)
            c++;
        if(num==false)
            c++;
        if(sc==false)
            c++;
        if(n+c>6)
            return c;
        else
        {
            int x=6-(n+c);
            return c+x;
        }
    }

    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();
    }
}