#include <bits/stdc++.h>
using namespace std;
const long long MOD=1e9+7;
long long dp[25][(1<<21)+10];
vector<int> sum[25];
int n,a[25][25];

int main(){
	cin>>n;
	for(int i=1;i<=n;++i)
		for(int j=0;j<n;++j) cin>>a[i][j];
	for(int i=0;i<(1<<n)-1;++i) sum[__builtin_popcount(i)].push_back(i);
	dp[0][0]=1;
	for(int i=1;i<=n;++i){
		for(vector<int>::iterator it=sum[i-1].begin();it!=sum[i-1].end();++it){
			int x=*it;
			for(int j=0;j<n;++j){
				if(!a[i][j]||x&(1<<j)) continue;
				(dp[i][x|(1<<j)]+=dp[i-1][x])%=MOD;
			}
		}
	}
	cout<<dp[n][(1<<n)-1]<<endl;
	return 0;
}
### Prompt

Your task is to create 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 long long MOD=1e9+7;
long long dp[25][(1<<21)+10];
vector<int> sum[25];
int n,a[25][25];

int main(){
	cin>>n;
	for(int i=1;i<=n;++i)
		for(int j=0;j<n;++j) cin>>a[i][j];
	for(int i=0;i<(1<<n)-1;++i) sum[__builtin_popcount(i)].push_back(i);
	dp[0][0]=1;
	for(int i=1;i<=n;++i){
		for(vector<int>::iterator it=sum[i-1].begin();it!=sum[i-1].end();++it){
			int x=*it;
			for(int j=0;j<n;++j){
				if(!a[i][j]||x&(1<<j)) continue;
				(dp[i][x|(1<<j)]+=dp[i-1][x])%=MOD;
			}
		}
	}
	cout<<dp[n][(1<<n)-1]<<endl;
	return 0;
}
```