#include <bits/stdc++.h>

using namespace std;
string num = "1234567890", low = "abcdefghijklmnopqrstuvwxyz", hi = "ABCDEFGHIJKLMNOPQRSTUVWXYZ", cha = "!@#$%^&*()_+-";
typedef long long int ll;
ll minimumNumber(ll n, string password) {
    ll con=0;
  
        bool mayup=false,maynum=false,maydown=false,maychar=false;
        
            for(ll i=0; i<n; i++)
            {
                ll op = (ll) password[i];
               // cout<<op<<endl;
                for(ll j=0; j<num.size(); j++)
                    if(password[i] == num[j])
                    maynum=true;
                for(ll j=0; j<hi.size(); j++)
                 if(password[i] == hi[j])
                    mayup=true;
                for(ll j=0; j<low.size(); j++)
                if(password[i] == low[j])
                    maydown=true;
                for(ll j=0; j<cha.size(); j++)
                {
                    if( password[i] == cha[j])
                        maychar=true;
                }
            }
        
       if(!maynum)
           con++;
        if(!mayup)
            con++;
        if(!maydown)
            con++;
        if(!maychar)
            con++;  
        if(n+con>=6)
        return con;
    else{
        return 6-n;
    }
      
    
    
}

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