#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    int count=0;
    if(n==1)
        return 5;
    //cout<<"5"<<endl;
           if(n==2)
               return 2;
               //cout<<"4"<<endl;
           else if(n==3)
               return 3;
                //cout<<"3"<<endl;
    int i=0;
           else if(n>3) 
           {int c1=0,c2=0,c3=0,c4=0,
               for i=0;i<n;i++)
            {if(password[i]>=65&&password[i]<=90)
                c1=1;
                    if(password[i]>=97&&password[i]<=122)
                        c2=1;
             if(password[i]>=48&&password[i]<=57)
                 c3=1;
             if(password[i]>=33&&password[i]<=45)
                 c4=1;
             
                
            }if(c1=0)
                   count++;
            if(c2=0)
                count++;
            if(c3=0)
                count++;
            if(c4=0)
                count++;
            cout<<count<<endl;
            return -1;
               // return count;
           }
           return count;
    // 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);
    if(answer!=-1)
    cout << answer << endl;
    return 0;
}