#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pf push_front;
#define fbo find_by_order
#define ook order_of_key
#define lb lower_bound
#define ub upper_bound
#define rep(i,n) for(int i=0;i<n;i++)
#define fo(j,a,b) for(int j=a;j<=b;j++)
#define mem(x,a) memset(x,a,sizeof(x))

typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef long double ld;
typedef map<ll,ll> spt;
typedef set<ll> si;
typedef multiset<ll>::iterator sit;
typedef map<int,int>::iterator mi;
typedef vector<int>::iterator vit;
typedef vector<ii> vii;
typedef set<ii> sii;
typedef multiset<ll> msi;
typedef vector< vector<ll> > matrix;
typedef tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update> ost;
typedef tree<ii,null_type,greater<ii>,rb_tree_tag,tree_order_statistics_node_update> ost1;
const ll INF = 1e18;
const int MOD = 1e9 + 7;
const int N = 1e6 +5;
char c[N];
vii adj[N];
ll vis[N];
ll w[502][502];
map<char,ll> gm;

int main()
{
    int n,k;
    cin>>n;
    string s;
    cin>>s;
    ll f1=1,f2=1,f3=1,f4=1;
    rep(i,n)
    {
        if(s[i]>='0' && s[i]<='9')
            f1=0;
        else if(s[i]>='a' && s[i]<='z')
            f2=0;
        else if(s[i]>='A' && s[i]<='Z')
            f3=0;
        else
        f4=0;
    }
    cout<<max(6ll-n,f1+f2+f3+f4);
}