#include <bits/stdc++.h>

using namespace std;

#define sqr(x) ((x) * (x))
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define fin(name) freopen(name, "r", stdin)
#define fout(name) freopen(name, "w", stdout)
#define I(x, a) for(auto x : a)
#define F(i, l, r) for(auto i = l; i != r; ++i)
#define DF(i, l, r) for(auto i = l; i != r; --i)
#define clean(a) memset((a),0,sizeof (a))
#define sync ios_base::sync_with_stdio(0);cin.tie(0)
#define all(x) x.begin(),x.end()
#define ret return
#define cont continue
#define brk break
#define ins insert
#define sz(a) ((int)(a).size())

typedef long long ll;
typedef unsigned long long ull;
typedef long double dbl;
typedef pair <int, int> pii;

const int inf = (int)1e9;
const ll linf = (ll)1e18;
const int mod = (int) 1e9 + 7;
const dbl eps = (dbl) 1e-8;
const int maxn = (int) 1e5 + 5;
const dbl pi = acos(-1);

string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";

int main()
{
//    fin("t.in");
    sync;
    int n;
    string s;
    int f_num = 0, f_low = 0, f_up = 0, f_sp = 0;
    cin >> n;
    cin >> s;
    F(j, 0, n) {
    	F(i, 0, sz(numbers))
    		if (s[j] == numbers[i])
    			f_num = 1;
    	F(i, 0, sz(lower_case))
    		if (s[j] == lower_case[i])
    			f_low = 1;
    	F(i, 0, sz(upper_case))
    		if (s[j] == upper_case[i])
    			f_up = 1;
    	F(i, 0, sz(special_characters))
    		if (s[j] == special_characters[i])
    			f_sp = 1;
    }
    cout << max(!f_sp + !f_low + !f_up + !f_num, 6 - sz(s)) << endl;

    return 0;
}