#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 result=0;
    bool num=false,low=false,upp=false,spec=false;
    for(int i=0;i<n;++i)
    {
        if(numbers.find(password[i]) != string::npos)
        {
            num = true;
        }
        else if(lower_case.find(password[i]) != string::npos)
        {
            low =true;
        }
        else if(upper_case.find(password[i]) != string::npos)
        {
            upp = true;
        }
        else if(special_characters.find(password[i]) != string::npos)
        {
            spec = true;
        }
    }
    if(!num)
    {
        result++;
    }
    if(!low)
    {
        result++;
    }
    if(!upp)
    {
        result++;
    }
    if(!spec)
    {
        result++;
    }
    if(result+n < 6)
    {
        return 6 - n;
    }
    else
    {
        return result;
    }
}

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