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) {
        // Return the minimum number of characters to make the password strong
       char special[] = {'!','@','#','$','%','^','&','*','(',')','-','+'};
        int k=4;
        int w=0,x=0,y=0,z=0;
        for(int i=0;i<n;i++)
        {
            char c = password.charAt(i);
            int d = (int)c;
            if(d>=48&&d<=57&&w==0)
            {
                k--;
                w=1;
            }
            
            if(d>=65&&d<=90&&x==0)
            {
                k--;
                x=1;
            }
            
            if(d>=97&&d<=122&&y==0)
            {
                k--;
                y=1;
            }
            
            if(z==0)
            {
                for(int j=0;j<12;j++)
                    if(c==special[j])
                    {
                        k--;
                        z=1;
                    }
            }
            
            
            
        }
        
       
           if(k+n<6)
                return 6-n;
            
            return k; 
        
    }

    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();
    }
}