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 req = 0;
        char[] a = password.toCharArray();
        String specialChars = "!@#$%^&*()-+";
        String lowerChars = "abcdefghijklmnopqrstuvwxyz";
        String upperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String numberChars = "0123456789";
        boolean specFlag = false, lowerFlag = false, upperFlag = false, numberFlag = false;
        for(int i=0; i<a.length; i++) {
            if(specialChars.contains(a[i]+"")) specFlag = true;
            if(lowerChars.contains(a[i]+"")) lowerFlag = true;
            if(upperChars.contains(a[i]+"")) upperFlag = true;
            if(numberChars.contains(a[i]+"")) numberFlag = true;
        }
        if(!specFlag) req++;
        if(!lowerFlag) req++;
        if(!upperFlag) req++;
        if(!numberFlag) req++;
        if(a.length + req < 6) req += 6 - (a.length + req);
        return req;
    }

    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();
    }
}