import java.io.*;
import java.util.*;
public class StrongPassword {
	
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
    
    static int minimumNumber(int n, String password) {
    	String[] caseStrings = {"0123456789", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", "!@#$%^&*()-+"};
    	// Return the minimum number of characters to make the password strong

    	//length
    	int len = 0;
    	if(password.length() < 6) {
    		len = 6 - password.length();  //num to add if too sthort
    	}
    	int reqs = 4;
    	//check for cases
    	boolean[] cases = new boolean[4]; //in order nums, lower, upper, special
    	for(int i = 0; i < password.length(); i++) {
    		char c= password.charAt(i);
    		for(int j = 0; j < 4; j++) {
        		if(!cases[j]) {
        			if(caseStrings[j].contains(c+"")) {
        				cases[j] = true;
        				reqs--;
        			}
        		}
    		}

    	}
    	return Math.max(len, reqs);
    }

}