import java.util.*;
public class strong
{
    public static void main(String []args)
    {
        Scanner sc=new Scanner(System.in);
        int n;
        n=sc.nextInt();
        int required=0;
        if(n<6)
        {
            required=6-n;
        }
        if(required>=3)
        {
            System.out.println(required);
        }
        else
        {
            String s;
            s=sc.next();
            int u=0;
            int l=0;
            int sp=0;
            int nm=0;
            for(int i=0;i<s.length() && (u==0 || l==0 || sp==0 || nm==0);i++)
            {
                char c=s.charAt(i);
                int ascii=(int)c;
                if(ascii>=48 && ascii<=57)
                {
                    nm=1;
                }
                else if(ascii>=65 && ascii<=90)
                {
                    u=1;
                }
                else if(ascii>=97 && ascii<=122)
                {
                    l=1;
                }
                else
                {
                    sp=1;
                }
            }
            int req=0;
            if(u==0)
            {
                req++;
            }
            if(l==0)
            {
                req++;
            }
            if(sp==0)
            {
                req++;
            }
            if(nm==0)
            {
                req++;
            }
            System.out.println(Math.max(required,req));
        }
    }
}