#include <iostream>
#include <string>
#include <cstdio>
#include <cstring>
#include <vector>
#include <queue>
#include <cmath>
#include <map>
#include <unordered_map>
using namespace std;

#define ff(i, n) for (int i = 0, END = (n); i < END; i ++)
#define fff(i, n, m) for (int i = (n), END = (m); i <= END; i ++)
#define dff(i, n, m) for (int i = (n), END = (m); i >= END; i --)
#define travel(e, first) for (int e = first, v = vv[first]; ~e; e = nxt[e], v = vv[e])
#define clr(a, b) memset(a, b, sizeof(a))
typedef long long ll;

int n, ans;
bool can[10][10];
bool done[10];

void input() {
    ans = 0;
    clr(can, 0);
    clr(done, 0);

    char s[10];
    fff (i, 1, n) {
        scanf("%s", s);
        ff (j, strlen(s)) {
            char now = s[j];
            can[i][now - '0'] = 1;
        }
    }
}

void solve(int c) {
    if (c == 0) {
        ans ++;
        return;
    }

    ff(i, 6) if (!done[i] && can[c][i]) {
        done[i] = true;
        solve(c - 1);
        done[i] = false;
    }
}

int main() {
    while (scanf("%d", &n) == 1) {
        input();
        solve(n);
        printf("%d\n", ans);
    }
}