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

const int maxn=(1<<21)-1,mod=1e9+7;
int n;
int a[32][32];
int dp[maxn+5];
int tmp[32];

int lowbit(int x){
	return x&(-x);
}

int main(){
	cin>>n;
	for(int i=0;i<n;++i){
		for(int j=0;j<n;++j){
			cin>>a[i][j];
			if(a[i][j]) tmp[i]|=(1<<j);
		}
	}
	dp[0]=1;
	for(int i=1;i<(1<<n);++i){
		int cnt=-1;
		int tt=i;
		while(tt) tt&=(tt-1),cnt++;
		tt=tmp[cnt];
		while(tt){
			int n_ow=lowbit(tt);
			tt=tt^n_ow;
			if((n_ow|i)==i) dp[i]+=dp[i^n_ow],dp[i]%=mod;
		}
	}
	cout<<dp[(1<<n)-1]<<"\n";
	return 0;
}
### Prompt

Your challenge is to write a cpp solution to the following problem:

There are N men and N women, both numbered 1, 2, \ldots, N.

For each i, j (1 \leq i, j \leq N), the compatibility of Man i and Woman j is given as an integer a_{i, j}. If a_{i, j} = 1, Man i and Woman j are compatible; if a_{i, j} = 0, they are not.

Taro is trying to make N pairs, each consisting of a man and a woman who are compatible. Here, each man and each woman must belong to exactly one pair.

Find the number of ways in which Taro can make N pairs, modulo 10^9 + 7.

Constraints

* All values in input are integers.
* 1 \leq N \leq 21
* a_{i, j} is 0 or 1.

Input

Input is given from Standard Input in the following format:


N
a_{1, 1} \ldots a_{1, N}
:
a_{N, 1} \ldots a_{N, N}


Output

Print the number of ways in which Taro can make N pairs, modulo 10^9 + 7.

Examples

Input

3
0 1 1
1 0 1
1 1 1


Output

3


Input

4
0 1 0 0
0 0 0 1
1 0 0 0
0 0 1 0


Output

1


Input

1
0


Output

0


Input

21
0 0 0 0 0 0 0 1 1 0 1 1 1 1 0 0 0 1 0 0 1
1 1 1 0 0 1 0 0 0 1 0 0 0 0 1 1 1 0 1 1 0
0 0 1 1 1 1 0 1 1 0 0 1 0 0 1 1 0 0 0 1 1
0 1 1 0 1 1 0 1 0 1 0 0 1 0 0 0 0 0 1 1 0
1 1 0 0 1 0 1 0 0 1 1 1 1 0 0 0 0 0 0 0 0
0 1 1 0 1 1 1 0 1 1 1 0 0 0 1 1 1 1 0 0 1
0 1 0 0 0 1 0 1 0 0 0 1 1 1 0 0 1 1 0 1 0
0 0 0 0 1 1 0 0 1 1 0 0 0 0 0 1 1 1 1 1 1
0 0 1 0 0 1 0 0 1 0 1 1 0 0 1 0 1 0 1 1 1
0 0 0 0 1 1 0 0 1 1 1 0 0 0 0 1 1 0 0 0 1
0 1 1 0 1 1 0 0 1 1 0 0 0 1 1 1 1 0 1 1 0
0 0 1 0 0 1 1 1 1 0 1 1 0 1 1 1 0 0 0 0 1
0 1 1 0 0 1 1 1 1 0 0 0 1 0 1 1 0 1 0 1 1
1 1 1 1 1 0 0 0 0 1 0 0 1 1 0 1 1 1 0 0 1
0 0 0 1 1 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1
1 0 1 1 0 1 0 1 0 0 1 0 0 1 1 0 1 0 1 1 0
0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 0 0 1
0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 0 0 1 1 0 1
0 0 0 0 1 1 1 0 1 0 1 1 1 0 1 1 0 0 1 1 0
1 1 0 1 1 0 0 1 1 0 1 1 0 1 1 1 1 1 0 1 0
1 0 0 1 1 0 1 1 1 1 1 0 1 0 1 1 0 0 0 0 0


Output

102515160

### Response

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

const int maxn=(1<<21)-1,mod=1e9+7;
int n;
int a[32][32];
int dp[maxn+5];
int tmp[32];

int lowbit(int x){
	return x&(-x);
}

int main(){
	cin>>n;
	for(int i=0;i<n;++i){
		for(int j=0;j<n;++j){
			cin>>a[i][j];
			if(a[i][j]) tmp[i]|=(1<<j);
		}
	}
	dp[0]=1;
	for(int i=1;i<(1<<n);++i){
		int cnt=-1;
		int tt=i;
		while(tt) tt&=(tt-1),cnt++;
		tt=tmp[cnt];
		while(tt){
			int n_ow=lowbit(tt);
			tt=tt^n_ow;
			if((n_ow|i)==i) dp[i]+=dp[i^n_ow],dp[i]%=mod;
		}
	}
	cout<<dp[(1<<n)-1]<<"\n";
	return 0;
}
```