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) {
        // Return the minimum number of characters to make the password strong
        int v[] = {0, 0, 0, 0};
    	for (int i = 0; i < n; i++) {
            if (Character.isDigit(password.charAt(i)))
            	v[0] = 1;
            else if (Character.isLowerCase(password.charAt(i)) && Character.isAlphabetic(password.charAt(i)))
            	v[1] = 1;
            else if (Character.isUpperCase(password.charAt(i)) && Character.isAlphabetic(password.charAt(i)))
            	v[2] = 1;
            else if (password.charAt(i) == '!' ||
            		password.charAt(i) == '@' ||
            				password.charAt(i) == '#' ||
            						password.charAt(i) == '%' ||
            								password.charAt(i) == '^' ||
            										password.charAt(i) == '&' ||
            												password.charAt(i) == '*' 
            												||password.charAt(i) == '(' ||
            														password.charAt(i) == ')' ||
            																password.charAt(i) == '-' ||
            																password.charAt(i) == '$' ||
            																password.charAt(i) == '+')
            	
            	v[3] = 1;
            	
        }
    	int remaining = 6 - n;
    	int nn = 0;
    	for (int i = 0; i < 4; i++) {
    		if (v[i] == 0)
    			nn++;
    	}
    	return Math.max(remaining, nn);
    }

    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();
    }
}