#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
  
    
    //check for lower case, upper case, special chars.
    bool lowerCase=false,upperCase=false,specialChar=false,number=false;
    for(char ch : password)
    {
        if('a' <= ch && 'z' >=ch)
            lowerCase=true;
        else if('A' <= ch && 'Z' >=ch)
            upperCase=true;
        else if('0' <= ch && '9' >=ch)
            number=true;
        else if(ch=='"' || ch=='!' || ch=='@'|| ch=='#'|| ch=='$'|| ch=='%'|| ch=='^'|| ch=='&'|| ch=='*'|| ch=='(' 
               || ch=='+'|| ch=='-'|| ch==')')
            specialChar=true;
            
            //"!@#$%^&*()-+"
        
    }
    
    int num = 0;
    if(lowerCase == false)
        num++;
    if(upperCase == false)
        num++;
    if(number == false)
        num++;
    if(specialChar == false)
        num++;
    
      if(password.length() +num <6)
        return 6 - password.length();
    
    return num;
    
}

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