#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
  string  numbers = "0123456789";
  string  lower_case = "abcdefghijklmnopqrstuvwxyz";
  string  upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
   string special_characters = "!@#$%^&*()-+";
    int ans=0;
    int flag;
    flag=0;
      for(int i=0;i<n;i++){
          for(int j=0;j<numbers.length();j++){
              if(numbers[j]==password[i]){
                  flag=1;
                  break;
              }
          }
      }
    if(flag==0)
        ans++;
    flag=0;
      for(int i=0;i<n;i++){
          for(int j=0;j<upper_case.length();j++){
              if(upper_case[j]==password[i]){
                  flag=1;
                  break;
              }
          }
      }
    if(flag==0)
        ans++;
    flag=0;
      for(int i=0;i<n;i++){
          for(int j=0;j<special_characters.length();j++){
              if(special_characters[j]==password[i]){
                  flag=1;
                  break;
              }
          }
      }
    if(flag==0)
        ans++;
    flag=0;
      for(int i=0;i<n;i++){
          for(int j=0;j<lower_case.length();j++){
              if(lower_case[j]==password[i]){
                  flag=1;
                  break;
              }
          }
      }
    if(flag==0)
        ans++;
    if(ans+n<6){
        return (ans+(6-n-ans));
    }
    else
        return ans;
    // Return the minimum number of characters to make the password strong
}

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