#include <bits/stdc++.h>

using namespace std;

std::string numbers = "0123456789";
std::string lower_case = "abcdefghijklmnopqrstuvwxyz";
std::string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
std::string special_characters = "!@#$%^&*()-+";
    
int minimumNumber(int n, string password) {
    bool lower =false, upper = false, special = false, digit = false;
    auto length = password.size();
    for (auto c : password)
    {
        if (std::isalpha(c))
        {
            if (c == std::tolower(c))
            {
                lower = true;
            }
            else
            {
                upper = true;
            }
        }
        else if (std::isdigit(c))
        {
            digit = true;
        }
        else
        {
            special = true;
        }
    }
    int add = 0;
    if (!lower) add++;
    if (!upper) add++;
    if (!digit) add++;
    if (!special) add++;
    if (add + length <= 6)
    {
        add += 6 - (length + add);
    }
    return add;
}

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