#include<iostream> 
using namespace std; 
const int N = 20 + 10; 
const int INF = 0x3f3f3f; 
int ans,n; 
char a[N][N]; 
bool v[N]; 
void dfs(int step)
{ 
    if(step == n + 1)
	{ 
	    ans++; 
		return; 
	} 
	for(int i = 1;i <= n;i++)
	{ 
	    if(a[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 >> a[i][j]; 
		} 
	} 
	dfs(1); 
	cout << ans;
	return 0; 
	}

#include using namespace std; const int N = 20 +10; const int INF=0x3f3f3f; int ans,n; char a[N][N]; bool v[N]; void dfs(int step){ if(step == n + 1){ ans++; return; } for(int i = 1;i<=n;i++){ if(a[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>>a[i][j]; } } dfs(1); cout<<ans; }