#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 = "!@#$%^&*()-+";
    int lenFlag = 0, num = 0, lc = 0, uc = 0, sc = 0;
    int len = 0;
    if (n < 6)
        len = 6-n;
    for (int i = 0 ; i < n ; i++)
    {
        if (numbers.find(password[i]) !=std::string::npos)
        {
           num =1;
        }
        if (lower_case.find(password[i]) !=std::string::npos)
        {
            lc =1;
        }
        if (upper_case.find(password[i]) !=std::string::npos)
        {
            uc =1;
        }
        if (special_characters.find(password[i]) !=std::string::npos)
        {
            sc =1;
        }
        if (num == 1 && lc == 1 && uc == 1 && sc ==1)
            break;
    }
    int tempLen = 0;
    if (num == 0)
        ++tempLen;
    if (sc == 0)
        ++tempLen;
    if (uc == 0)
        ++tempLen;
    if (lc == 0)
        ++tempLen;
    if (len > tempLen)
        return len;
    else
        return tempLen;
    // Return the minimum number of characters to make the password strong
}

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