#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 one=0, two=0, i;
    string str = password;
    bool dig = false, lc = false, uc = false, sp = false;
    one = max(0,6-n);
    for (i=0;i<n;i++)
    {
        if (str[i] >= '0' && str[i] <= '9')
            dig = true;
        if (str[i] >= 'a' && str[i] <= 'z')
           lc = true;
        if (str[i] >= 'A' && str[i] <= 'Z')
           uc = true;
      //  !@#$%^&*()-+
        if (str[i] == '!' || str[i] == '@' ||str[i] == '$' ||str[i] == '%' ||str[i] == '^' ||str[i] == '&' ||str[i] == '*' ||str[i] == '(' ||str[i] == ')' ||str[i] == '-' ||str[i] == '+' ||str[i] == '#')
            sp = true;
    }
    if (dig == false)
        two++;
    if (lc == false)
        two++;
    if (uc == false)
        two++;
    if (sp == false)
        two++;
    return max(one,two);
}

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