#include <bits/stdc++.h>

using namespace std;
string numbers = "012345678911" ;
string lower_case = "abcdefghijklmnopqrstuvwxyz" ;
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" ;
string special_characters = "!@#$%^&*()-+" ;
int minimumNumber(int n, string password) {
   int  sum = 0 , sum2 =0  , nu = 0 , lo = 0 , up = 0 , sp = 0  ;
    for(int i = 0 ;i< n ;i++){
      for(int j=0 ;  j<lower_case.size();j++){
        if(lower_case.at(j) == password.at(i))
                lo++ ;
        if(upper_case.at(j) == password.at(i))
                up++ ;
      }
      for(int m=0 ;  m<numbers.size();m++){
        if(numbers.at(m) == password.at(i))
                nu++ ;

         if(special_characters.at(m) == password.at(i))
                sp++ ;
    }
    }
    if(nu==0) sum++;
     if(lo==0) sum++;
      if(up==0) sum++;
       if(sp==0) sum++;
       if(password.size() < 6)
            sum2 = 6 - password.size() ;
      if(sum >sum2)
         return  sum ;
    else
        return sum2 ;
}

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