#include <vector>
#include <iostream>
#include <algorithm>
#ifdef D0N14
#define d(...) __VA_ARGS__
#else
#define d(...) 
#endif
#define all(x) (x).begin(), (x).end()
#define eb(...) emplace_back(__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef ostream os;os& e=cerr;
typedef unsigned long long ull;
template<typename t>using V=vector<t>;
template <template<typename...> 
class ct,typename vt,typename... A>
os& operator<<(os& s,const ct<vt,A...>&c)
{for(const auto& a:c)s<<a<<' ';return s;}

V< string > tab = { "0123456789", "abcdefghijklmnopqrstuvwxyz",
"ABCDEFGHIJKLMNOPQRSTUVWXYZ", "!@#$%^&*()-+" };
V< bool > fl = V< bool >( 4 );

string sl;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n; cin >> n >> sl;
    for ( int i = 0; i < n; ++i )
        for ( int k = 0; k < 4; ++k )
            for ( int j = 0; j < tab[k].size(); ++j )
                if ( tab[k][j] == sl[i] )
                    fl[k] = true;
    int res = 0;
    for ( int i = 0; i < 4; ++i )
        if ( fl[i] == false )
            ++res;
    res = max( res, 6 - (int)sl.size() );
    cout << res << '\n';
}