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

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

using namespace std;

bool isSpecial(char ch)
{
    for( int i=0; i<special_characters.size(); i++ )
    {
        if( ch==special_characters[i] )
            return true;
    }
    return false;
}

bool isUpper(char ch)
{
    for( int i=0; i<upper_case.size(); i++ )
    {
        if( ch==upper_case[i] )
            return true;
    }
    return false;
}

bool isLower(char ch)
{
    for( int i=0; i<lower_case.size(); i++ )
    {
        if( ch==lower_case[i] )
            return true;
    }
    return false;
}

bool isDigit(char ch)
{
    for( int i=0; i<numbers.size(); i++ )
    {
        if( ch==numbers[i] )
            return true;
    }
    return false;
}

/*
Its length is at least .
It contains at least one digit.
It contains at least one lowercase English character.
It contains at least one uppercase English character.
It contains at least one special character. The special characters are: !@#$%^&*()-+
*/

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    
    bool containsDigit = false;
    bool containsLower = false;
    bool containsUpper = false;
    bool containsSpecial = false;
    for( int i=0; i<n; i++ )
    {
        char ch = password[i];
        if( isDigit(ch) )
            containsDigit = true;
        else if( isLower(ch) )
            containsLower = true;
        else if( isUpper(ch) )
            containsUpper = true;
        else if( isSpecial(ch) )
            containsSpecial = true;
    }
    
    int req = 0;
    
    if( containsDigit==false )
        req++;
    if( containsLower==false )
        req++;
    if( containsUpper==false )
        req++;
    if( containsSpecial==false )
        req++;

    int reqSize = 0;
    if( password.size() < 6 )
        reqSize = 6-password.size();
    
    return req>reqSize ? req : reqSize;
}

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