import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {


    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String lower = new String("abcdefghijklmnopqrstuvwxyz");
        String upper = new String("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        String digit = new String("0123456789");
        String special = new String("!@#$%^&*()-+");
        int fl=0,fu=0,fd=0,fs=0;
        String pa = in.next();
        
        for(int i=0;i<n;i++){
            int l = lower.indexOf(pa.charAt(i));
            int u = upper.indexOf(pa.charAt(i));
            int d = digit.indexOf(pa.charAt(i));
            int s = special.indexOf(pa.charAt(i));
            if(l>=0){
                fl=1;
            }else if(u>=0){
                fu=1;
            }else if(d>=0){
                fd=1;
            }else if(s>=0){
                fs=1;
            } 
        }
        int count=0,x;
        if(fl!=1){
            count++;
        }
        if(fu!=1){
            count++;
        }
        if(fd!=1){
            count++;
        }
        if(fs!=1){
            count++;
        }
        
        if(pa.length()<6)
        {
            x = (6-pa.length());
            if(count<x){
                count=x;
            }
        }
        
        System.out.println(count);
        in.close();
    }
}