#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
typedef long long int lld;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define trav(a,v) for(auto a:v)
vector<pair<int,int> >V;
int arr[100];
bool works[(1<<20)];
lld DP[(1<<20)];
void solve(){
	int n;
	cin>>n;
	int m;
	cin>>m;
	rep(i,0,m){
		int x,y;
		cin>>x>>y;
		x--;y--;
		V.push_back({x,y});
	}
	rep(msk,0,(1<<n)){
		rep(i,0,n){
			arr[i]=(msk>>i)%2;
			//cout<<arr[i];
		}
		rep(i,0,m){
			if(arr[V[i].first]>arr[V[i].second])swap(arr[V[i].first],arr[V[i].second]);
		}
		works[msk]=true;
		rep(i,0,n-1){
			if(arr[i]>arr[i+1]){
				works[msk]=false;
			}
		}
		//cout<<" "<<works[msk]<<"\n";
	}
	DP[0]=1;
	rep(msk,1,(1<<n)){
		DP[msk]=0;
		if(works[msk]){
			rep(i,0,n){
				if((msk&(1<<i))>0){
					DP[msk]+=DP[msk-(1<<i)];
				}
			}
		}
		//cout<<msk<<" "<<DP[msk]
	}
	lld fact=1;
	rep(i,1,n+1)fact*=i;
	cout<<fact-DP[(1<<n)-1]<<"\n";
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int tt=1;
	//cin>>tt;
	while(tt--){
		solve();
	}
}