#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
        
    bool hasNumber = false;
    bool hasLower = false;
    bool hasUpper = false;
    bool hasSpecial = false;
        
    int x = 0;
    
    for (int i = 0; i < n; ++i){
        for (int j = 0; j < numbers.length(); ++j)if (password[i] == numbers[j]) hasNumber = true;
        for (int j = 0; j < lower_case.length(); ++j)if (password[i] == lower_case[j]) hasLower = true;
        for (int j = 0; j < upper_case.length(); ++j)if (password[i] == upper_case[j]) hasUpper = true;
        for (int j = 0; j < special_characters.length(); ++j)if (password[i] == special_characters[j]) hasSpecial = true;
    }
    
    if (!hasNumber) x++;
    if (!hasLower) x++;
    if (!hasUpper) x++;
    if (!hasSpecial) x++;
    
    if (n < 6) x = max(6 - n, x);
    return x;
}

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