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 l=password.length();
    int count=0;
      
      int cap=0;
      int small=0;
      int digit=0;
      int symbol=0;
    		 
      for(int i=0;i<l;i++){
    	  if(password.charAt(i)>=65&&password.charAt(i)<=90)
    		  cap=1;
    	  if(password.charAt(i)>=97 && password.charAt(i)<=122)
    		  small=1;
    	  if(password.charAt(i)>=48 &&password.charAt(i)<=57)
    		  digit=1;
    	  if(!(password.charAt(i)>=65&&password.charAt(i)<=90)&&!(password.charAt(i)>=97 && password.charAt(i)<=122)&&!(password.charAt(i)>=48 &&password.charAt(i)<=57))
    		  symbol=1;
    	  
    	  
    			  
    	  }
      if(l<6){
    	  if(cap==0)
    		  {count++;
    		  l++;}
    	  if(small==0){
    		  count++;
    		  l++;
    	  }
    		  if(symbol==0){
    			  count++;
    		  l++;
    		  }
    		  if(digit==0){
    			  count++;
    			  l++;
    		  }
    		if(l<6)
    		{
    			count=(6-l)+count;
    		}
      }
      else{
    	  if(cap==0)
		  {count++;
		  }
	  if(small==0){
		  count++;
		 
	  }
		  if(symbol==0){
			  count++;
		 
		  }
		  if(digit==0){
			  count++;
			  
		  }  
      }
      return count;
    	// Return the minimum number of characters to make the password strong
    }

    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();
    }
}