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) {
        boolean up = false;
            boolean low = false;
            boolean dight = false;
            boolean spc = false;
        for(int i = 0; i < n; i++){
            int ascii = (int)password.charAt(i);
            
            
            if(ascii >= 65 && ascii <= 90){
                up = true;
            }
            else if(ascii >= 97 && ascii <= 122){
                low = true;
            }
            else if(ascii >= 48 && ascii <= 57){
                dight = true;
            }
            else if(ascii == 33 || ascii == 64 || ascii == 35 || ascii == 36 || ascii == 37 || ascii == 94 || ascii == 38 || ascii == 40 || ascii == 41 || ascii == 42 || ascii == 43 || ascii == 45 ){
                spc = true;
            }
            
        }
        int ans = 0;
            if(!up){
                ans ++;
            }
            if(!low){
                ans ++;
            }
        if(!dight){
                ans ++;
            }
        if(!spc){
                ans ++;
            }
        if(ans + n < 6){
            ans = 6-n;
        }
        return ans;
    }

    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();
    }
}