#include <bits/stdc++.h>

#define F first
#define S second
#define pb push_back
#define ll long long
#define ld long double
#define FILE "answer"
#define pii pair <int,int>

using namespace std;

const int mod = 1e9 + 7;
const int INF = 1e9;

int bad[1005];
string s, ss[10005];
int f[1005][228];
int cnt[228];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    int n;
    cin >> n;
    // string s;
    cin >> s;
    int kc = 0;
    for (int i=0; i<n; i++) {
        bad[s[i]] = 1;
        kc += s[i] == '*';
    }
    int m;
    cin >> m;
    for (int i=0; i<m; i++) {
        cin >> ss[i];
    }
    vector <string> good;
    int res = 0;
    for (int i=0; i<m; i++) {
        int f = 0;
        for (int j=0; j<n; j++) {
            if (bad[ss[i][j]] && s[j] == '*') {
                f = 1;
                break;
            }
            if (s[j] != '*' && ss[i][j] != s[j]){
                f = 1;
                break;
            }
        }
        if (!f) good.pb(ss[i]);
    }
    for (int i=0; i<good.size(); i++) {
        for (auto x : good[i]) {
            if (bad[x]) continue;
            if (!f[i][x]) cnt[x]++;
            f[i][x] = 1;
        }
    }
    for (int i=0; i<228; i++) {
        if (!bad[i]) res += cnt[i] == good.size();
    }
    cout << res << endl;
}