#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) 
{
    int d,l,u,s;
    d=0;
    l=0;
    u=0;
    s=0;
    for(int i=0;i<password.size();i++)
    {
        if(password[i]>='0'&&password[i]<='9')
        {
            d++;
        }
         else if(password[i]>='a'&&password[i]<='z')
        {
            l++;
        }
         else if(password[i]>='A'&&password[i]<='Z')
        {
            u++;
        }
         else
        {
            s++;
        }
    }
    int cr=0;
    if(d==0)
    {
        cr++;
    }
    if(l==0)
    {
        cr++;
    }
    if(u==0)
    {
        cr++;
    }
    if(s==0)
    {
        cr++;
    }
    if(password.size()+cr<6)
    {
        cr+=(6-password.size()-cr);
    }
    return cr;
}

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