import java.util.*;
public class HR1
{
    public static void main(String[] args)
    {
        Scanner in =new Scanner(System.in);
        int n=Integer.parseInt(in.nextLine());
        String s=in.nextLine();
        int[] arr=contSpecChar(s);
        int add=0;
        for(int i=0;i<4;i++)
        {
            if(arr[i]==0)add++;
        }
        if(add+n>=6)
        {
            System.out.println(add);
        }
        else
        {
            System.out.println(6-n);
        }
    }

    private static int[] contSpecChar(String s)
    {
        int n=s.length();
        int[] arr=new int[4];
        for(int i=0;i<n;i++)
        {
            char ch=s.charAt(i);
            if(ch=='!' || ch=='@' || ch=='#'
               || ch=='$' || ch=='%' || ch=='^'
               || ch=='&' || ch=='*' || ch=='('
               || ch==')' || ch=='-' || ch=='+')
                arr[3]=1;
            if(ch>='0' && ch<='9')arr[0]=1;
            if(ch>='a' && ch<='z')arr[1]=1;
            if(ch>='A' && ch<='Z')arr[2]=1;
        }
        return arr;
    }

}