#include <bits/stdc++.h>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define EACH(it,a) for(__typeof(a.begin()) it = a.begin(); it != a.end(); ++it)

#define DEBUG(x) { cout << #x << " = "; cout << (x) << endl; }
#define PR(a,n) { cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl; }
#define PR0(a,n) { cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl; }

#define sqr(x) ((x) * (x))
#define llint long long

using namespace std;

string s, t = "!@#$%^&*()-+";
int n, ans = 4;

int main()
{
    cin>> n;
    cin>> s;
    bool a1, a2, a3, a4;
    a1 = a2 = a3 = a4 = 0;
    REP(i, s.length()){
        if ('a' <= s[i] && s[i] <= 'z') a1 = 1;
        if ('A' <= s[i] && s[i] <= 'Z') a2 = 1;
        if ('0' <= s[i] && s[i] <= '9') a3 = 1;
        REP(j, t.length()) if (s[i] == t[j]) a4 = 1;
    }
    if (a1) ans--;
    if (a2) ans--;
    if (a3) ans--;
    if (a4) ans--;
    cout<< max(ans, 6 - (int)s.length());

}