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 pass) {
        // Return the minimum number of characters to make the password strong
        int l=pass.length();
        int dig=0,sym=0,low=0,cap=0,count=0;
        for(int i=0;i<l;i++)
        {
            if((int)pass.charAt(i)>=48&&(int)pass.charAt(i)<=57)
                dig++;
            if((int)pass.charAt(i)>=65&&(int)pass.charAt(i)<=90)
                cap++;
            if((int)pass.charAt(i)>=97&&(int)pass.charAt(i)<=122)
                low++;
                                    if(pass.charAt(i)=='!'||pass.charAt(i)=='@'||pass.charAt(i)=='#'||pass.charAt(i)=='$'||pass.charAt(i)=='%'||pass.charAt(i)=='^'||pass.charAt(i)=='&'||pass.charAt(i)=='*'||pass.charAt(i)=='('||pass.charAt(i)==')'||pass.charAt(i)=='-'||pass.charAt(i)=='+')
                sym++;
        }
        if(dig==0)
            count++;
        if(cap==0)
            count++;
        if(sym==0)
            count++;
        if(low==0)
           count++;
        if(l+count<6)
          count=6-l;
        return count;
    }

    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();
    }
}