#include <bits/stdc++.h>
#include <map>
using namespace std;

int minimumNumber(int n, string password) {

    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    map<char,int> charMap;
    int flag1 = 0,flag2 = 0,flag3 = 0,flag4 = 0;
    // Return the minimum number of characters to make the password strong
    for(int i = 0; i < password.size(); i++)
    {
        charMap[password[i]]++;
    }   
    flag1 = 1;
    for(char s : numbers)
    {   
        if(charMap[s] > 0)
        {
            flag1 = 0 ;
            break;
        }
    }
    flag2 = 1;
    for(char l:lower_case)
    {
        if(charMap[l] > 0)
        {
            flag2 = 0 ;
            break;
        }
    }
    flag3 = 1; 
    for(char u : upper_case)
    {
        if(charMap[u] > 0)
        {
            flag3 = 0 ;
            break;
        }
    }
    flag4 = 1;
    for(char s : special_characters)
    {
        if(charMap[s] > 0)
        {
            flag4 = 0 ;
            break;
        }
    }
    int netFlag = flag1+flag2+flag3+flag4;
    if(n >= 6)
        return netFlag;
    else
    {
        if(n+netFlag >= 6)
            return netFlag;
        else
            return 6-n;
    }
}

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