#include <bits/stdc++.h> 
 
using namespace std;  
 
typedef long long ll;  
typedef pair<int, int> ii;  
 
const int INF = 1e9;  
const ll LINF = 1e18;  
 
const int MOD = 1e9 + 7;   
 
void add(int& a, int b) {
	a += b; 
	if (a >= MOD) a -= MOD;
}
 
int n, m; 
int adj_mat[20][20]; 
 
int dp[1 << 20][20]; // dp[mask][i] = Số đường đi xuất phát tại đỉnh 1, đã đi qua các đỉnh trong tập mask, 
					 //               mỗi đỉnh đi qua đúng một lần và kết thúc tại đỉnh i 
 
int main() {
	ios::sync_with_stdio(false); 
	cin.tie(nullptr); 	
	cin >> n >> m; 	
 
	for (int i = 0; i < m; i++) {
		int u, v; 
		cin >> u >> v; 
		--u, --v; 
		adj_mat[u][v]++; 
	}
 
	dp[1 << 0][0] = 1;   
	for (int mask = 0; mask < (1 << n); mask++) {
		for (int u = 0; u < n; u++) {
			if (dp[mask][u] == 0) continue; 
			for (int v = 0; v < n; v++) {
				if ((mask >> v) & 1) continue; 
				int next_mask = mask | (1 << v);  
				add(dp[next_mask][v], 1ll * dp[mask][u] * adj_mat[u][v] % MOD); 
			}
		}
	}
 
	cout << dp[(1 << n) - 1][n - 1] << '\n'; 
}

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

NCA2CjEgMgoxIDMKMiAzCjMgMgoyIDQKMyA0

4 6
1 2
1 3
2 3
3 2
2 4
3 4