#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
int a=0,b=0,c=0,d=0;   
   
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<10;j++)
            if(password[i]==numbers[j])
                a++;
        
        for(int j=0;j<26;j++)
        {
            if(password[i]==lower_case[j])
                b++;
            if(password[i]==upper_case[j])
                c++;
        }
        
        for(int j=0;j<12;j++)
        {
            if(password[i]==special_characters[j])
                d++;
        }
    }
    
int cnt=0;
    
if(a==0)
    cnt++;
if(b==0)
    cnt++;
if(c==0)
    cnt++;
if(d==0)
    cnt++;
    
if(n>=6 && cnt==0)
    return 0;
else if(n>=6)
    return cnt;
else if(n<6)
    return max(cnt,6-n);
return 0;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}