import java.util.*;

public class StrongPassword 
{

    public static void main(String[] args) 
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String pass = sc.next();
        /*if(n<6)
        {
            System.out.println(6-n);
            System.exit(0);
        }*/
        char ch;
        int flag1=0, flag2=0, flag3=0, flag4=0;
        for(int i=0; i<n; i++)
        {
            ch = pass.charAt(i);
            if((ch>='A' && ch<='Z'))
            {
                flag1 = 1;
            }
            else if((ch>='a' && ch<='z'))
            {
                flag2 = 1;
            }
            else if((ch>='0' && ch<='9'))
            {
                flag3 = 1;
            }
            else if(ch=='!'||ch=='@'||ch=='#'||ch=='$'||ch=='%'||ch=='^'||ch=='&'||ch=='*'||ch=='('||ch==')'||ch=='-'||ch=='+')
            {
                flag4 = 1;
            }
        }
        int x = 4-(flag1+flag2+flag3+flag4);
        if((6-(n+x))>0)
        {            
            System.out.println(6-n);
        }
        else
            System.out.println(x);
    }
    
}