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 s) {
        int l=n;int flagl=0,flagu=0,flagd=0,flags=0;
        for(int i=0;i<l;i++)
        {
            char c=s.charAt(i);
            if(Character.isUpperCase(c))
             flagu=1;
            if(Character.isLowerCase(c))
             flagl=1;
            if(Character.isDigit(c))
                flagd=1;
            if(c=='!'||c=='@'||c=='#'||c=='$'||c=='%'||c=='^'||c=='&'||c=='*'||c=='('||c==')'||c=='-'||c=='+')
                flags=1;
        }
        
            int cp=0;
            if(flagu==0)
               cp++;
            if(flagl==0)
                cp++;
            if(flagd==0)
                cp++;
            if(flags==0)
                cp++;
            
        
        if(l<6)
        {
            int lo=6-l;
             if((l+cp)>=6)
             return cp;
             else
             return lo;   
    }
        if(l>=6)
            return cp;
        return 0;
    }
    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();
    }
}