#include <bits/stdc++.h>

using namespace std;

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

int isOk(char x, string S)
{
    for(int i=0; i<S.size(); i++)
        if(S[i] == x)
            return 1;
    
    return 0;
}
    
int minimumNumber(int n, string password) {
    int ans1 = 0, ans2 = 0, ans3 = 0, ans4 = 0;
    
    for(int i=0; i<password.size(); i++)
    {
        ans1 |= isOk(password[i], numbers);
        ans2 |= isOk(password[i], lower_case);
        ans3 |= isOk(password[i], upper_case);
        ans4 |= isOk(password[i], special_characters);
    }
    
    int x = 4 - ans1 - ans2 - ans3 - ans4;
    
    return max(6-n, x);
}

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