#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

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

int main() {
    int n;
    cin >> n;
    
    string s;
    cin >> s;
    
    int size = s.length();
    
    int minimum = 0;
    
    bool contains_number = false;
    bool contains_lower_case = false;
    bool contains_upper_case = false;
    bool contains_special = false;    
    
    for (char c : s)
    {
        if (c >= '0' && c <= '9')
        {
            contains_number = true;            
        }
        if (c >= 'a' && c <= 'z')
        {
            contains_lower_case = true;
        }
        if (c >= 'A' && c <= 'Z')
        {
            contains_upper_case = true;
        }
        for (char c_special : special_characters)
        {
            if (c == c_special)
            {
                contains_special = true;
            }
        }
    }
    
    if (!contains_number) minimum++;
    if (!contains_lower_case) minimum++;
    if (!contains_upper_case) minimum++;
    if (!contains_special) minimum++;
    
    // cout << "minimum = " << minimum << endl;
    // cout << "Size = " << size << endl;
    
    minimum = max(6 - size, minimum);
    
    cout << minimum << endl;

    
    

    return 0;
}