#include<bits/stdc++.h> using namespace std;

const int MAXN = 25; int n, ans; char arr[MAXN][MAXN]; bool v[MAXN];

void dfs(int step) { if (step == n + 1) { ans++; return; } for (int i = 1; i <= n; i++) { if (arr[step][i] == '1' && !v[i]) { v[i] = 1; dfs(step + 1); v[i] = 0; } } }

int main() { cin >> n; for (int i = 1; i <= n; i++) { for (int j = 1; j <= n; j++) { cin >> arr[i][j]; } }

dfs(1);
cout << ans << endl;
return 0;

}