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) {
        int num=0,cap=0,small=0,special=0;
        for(int i=0;i<n;i++)
        {
            char ch=password.charAt(i);
            if(ch=='0'||ch=='1'||ch=='2'||ch=='3'||ch=='4'||ch=='5'||ch=='6'||ch=='7'||ch=='8'||ch=='9')
                num++;
            if(ch>=65&&ch<=90)
                cap++;
            if(ch>=97&&ch<=122)
                small++;
            if(ch=='!'||ch=='@'||ch=='#'||ch=='$'||ch=='%'||ch=='^'||ch=='&'||ch=='*'||ch=='('||ch==')'||ch=='-'||ch=='+')
                special++;
            
        }
        
        int answer=0;
        if(num==0)
            answer++;
        if(cap==0)
            answer++;
        if(small==0)
            answer++;
        if(special==0)
            answer++;
        if((n+answer)<6)
            answer=answer+(6-(n+answer));
        
        return answer;
    }

    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();
    }
}