#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#define ll long long
using namespace std;


int main() 
{
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    ll n;
    cin>>n;
    string s;
    cin>>s;
    ll f1=1,f2=1,f3=1,f4=1,f5=1;
    if(n>=6)
        f1=0;
    for(ll i=0;i<n;i++)
    {
        if(s[i]>='0' && s[i]<='9')
            f2=0;
        else if(s[i]>='a' && s[i]<='z')
            f3=0;
        else if(s[i]>='A' && s[i]<='Z')
            f4=0;
        else
            f5=0;
    }
    ll ans1=f2+f3+f4+f5;
    ll ans2=6-n;
    ll ans=max(ans1,ans2);
    cout<<ans<<"\n";
    return 0;
}