#include <bits/stdc++.h>
#include <string>

using namespace std;

string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
    
int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int numdeficit = 6 - password.size();
    bool haveNumber = any_of( password.cbegin(), password.cend(), []( char sym ){
        return find( numbers.cbegin(), numbers.cend(), sym ) != numbers.cend();
    } );
    bool haveLower = any_of( password.cbegin(), password.cend(), []( char sym ){
        return find( lower_case.cbegin(), lower_case.cend(), sym ) != lower_case.cend();
    } );
    bool haveUpper = any_of( password.cbegin(), password.cend(), []( char sym ){
        return find( upper_case.cbegin(), upper_case.cend(), sym ) != upper_case.cend();
    } );
    bool haveSpec = any_of( password.cbegin(), password.cend(), []( char sym ){
        return find( special_characters.cbegin(), special_characters.cend(), sym ) != special_characters.cend();
    } );
    auto retval = 0;
    if ( !haveNumber )
        ++retval;
    if ( !haveLower )
        ++retval;
    if ( !haveUpper )
        ++retval;
    if ( !haveSpec )
        ++retval;
    return max( retval, numdeficit );
}

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