#include <bits/stdc++.h>

using namespace std;

string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";


int minimumNumber(int n, string password) {
    int count = 4;
    bool has_num = false, has_lc = false, has_uc = false, has_sc = false;
    
    for (int i = 0; i < n; ++i) {
        char c = password[i];
        if (c >= '0' and c <= '9' and !has_num) {
            count--;
            has_num = true;
        } else if (c >= 'a' and c <= 'z' and !has_lc) {
            count--;
            has_lc = true;            
        } else if (c >= 'A' and c <= 'Z' and !has_sc) {
            count--;
            has_sc = true;
        } else if (special_characters.find(c) != std::string::npos and !has_uc) {
            count--;
            has_uc = true;
        }
    }
    
    if (n < 6) {
        count = std::max(count, 6 - n);
    }
    return count;
}

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