#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int main()
{
    ios_base::sync_with_stdio(false);
    
    ll n;
    cin>>n;
    
    string str;
    cin>>str;
    
    bool lower=false,upper=false,special=false,num=false;
    
    for (ll i=0;i<n;i++)
    {
        if (str[i]<='z' && str[i]>='a') lower=true;
        else if (str[i]<='Z' && str[i]>='A')    upper=true;
        else if ((str[i]-'0')<=9 && (str[i]-'0')>=0)    num=true;
        else    special=true;
    }
    
    ll cnt=4-lower-upper-num-special;
    
    ll rem=max(0LL,6-n);
    
    cnt=max(cnt,rem);
    
    cout<<cnt<<endl;
}