//--------------------------------Life is beautiful------------------------------------
#include<bits/stdc++.h>
#define Nilesh ios_base::sync_with_stdio(false);
using namespace std;
int main()
{
	Nilesh
	int n;
	cin>>n;
	string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
	string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
	string s;
	cin>>s;
	//int l=s.length();
	int req=4;
    int f1=0,f2=0,f3=0,f4=0;
	for(int i=0;i<n;i++)
	{
		int j=0;
		while(numbers[j]!='\0')
		{
			if(numbers[j]==s[i] && f1==0)
            {
				req--;
                f1=1;
                break;
            }
			j++;
		}
		j=0;
		while(lower_case[j]!='\0')
		{
			if(lower_case[j]==s[i] && f2==0)
            {
				req--;
                f2=1;
                break;
            }
			j++;	
		}
		j=0;
		while(upper_case[j]!='\0')
		{
			if(upper_case[j]==s[i] && f3==0)
            {
				req--;
                f3=1;
                break;
            }
			j++;
		}
		j=0;
		while(special_characters[j]!='\0')
		{
			if(special_characters[j]==s[i] && f4==0)
            {
				req--;
                f4=1;
                break;
            }
			j++;
		}
	}
	if(n>=6)
		cout<<req;
	else
		{
			if(n<6)
			{
				if(n+req>=6)
					cout<<req;
				else
					cout<<6-n;
			}
		}
}