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 result = 0;
        for(int i=0;i<n;i++){
            if((int)password.charAt(i)>=48 && (int)password.charAt(i)<=57){
                result=result+1;
                break;
            }
        }
        for(int i=0;i<n;i++){
            if((int)password.charAt(i)>=65 && (int)password.charAt(i)<=90){
                result=result+1;
                break;
            }
        }
        for(int i=0;i<n;i++){
            if((int)password.charAt(i)>=97 && (int)password.charAt(i)<=122){
                result=result+1;
                break;
            }
        }
        for(int i=0;i<n;i++){
            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)=='+' || password.charAt(i)=='{'){
                result=result+1;
                break;
            }
        }
        return result;
    }

    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);
        int solution = 0;
        if(answer<4){
            solution = 4-answer;
        }
       // n = n+solution;
        while(n+solution<6){
            solution++;
        }
        System.out.println(solution);
        in.close();
    }
}