#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int add = 0;
    
    char numbers[] = "0123456789";
    char lower_case[] = "abcdefghijklmnopqrstuvwxyz";
    char upper_case[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    char special_characters[] = "!@#$%^&*()-+";    
            
    if(password.find_first_of(numbers) == std::string::npos) add ++;
    if(password.find_first_of(lower_case) == std::string::npos) add ++;
    if(password.find_first_of(upper_case) == std::string::npos) add ++;
    if(password.find_first_of(special_characters) == std::string::npos) add ++;
    
    if(n < 6) add = max(add, 6-n);
    
    return add;
}

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