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

using namespace std;

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


bool isNumber( char c )
{
    return string::npos != numbers.find( c );
}


bool isLower( char c )
{
    return string::npos != lower_case.find( c );
}

bool isUpper( char c )
{
    return string::npos != upper_case.find( c );
}

bool isSpecial( char c )
{
    return string::npos != special_characters.find( c );
}


int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int count = 0;
    
    bool hasNum, hasLower, hasUpper, hasSpecial;
    
    hasNum = hasLower = hasUpper = hasSpecial = false;
    
    for( auto c: password )
    {
        if( isNumber( c )) hasNum = true;
        if( isLower(c) ) hasLower = true;
        if( isUpper(c)) hasUpper = true;
        if( isSpecial( c ) ) hasSpecial = true;
    }
    if( !hasNum ) count ++;
    if( !hasLower ) count ++;
    if( !hasUpper ) count ++;
    if( !hasSpecial ) count ++;
    
    if( n >= 6 ) return count;
    
    return max( 6 - n , count );
}

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