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 u=0,k=0,l=0,d=0,s=0;
        for(int i=0;i<n;i++){
            char ch=password.charAt(i);
            if (ch >= 'A' && ch <= 'Z')
                u++;
            else if (ch >= 'a' && ch <= 'z')
                l++;
            else if (ch >= '0' && ch <= '9')
                d++;
            else
                s++;
        }
        if(u==0)
            k++;
        if(l==0)
            k++;
        if(s==0)
            k++;
        if(d==0)
            k++;
        if(n+k<6)
            k=k+(6-(n+k));
        return k;
    }

    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();
    }
}