//Trumling ©
//Αφόδευε υψηλά και ηγνάντει
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define F first
#define S second
#define enter cout<<'\n';
#define INF 99999999999999999
#define MOD 998244353
#define all(x) x.begin(),x.end()
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n,m;
cin>>n>>m;
pair<ll,ll> arr[m];
vector<vector<bool>>g(n+1,vector<bool>(n+1,0));
for(int i=0;i<m;i++)
{
cin>>arr[i].F>>arr[i].S;
g[arr[i].F][arr[i].S]=1;
}
ll ans=0;
vector<ll>v;
for(int i=1;i<=n;i++)
v.pb(i);
set<ll>s;
do
{
ll curr=0;
ll id=0;
for(ll i=0;i<m;i++)
if(v[arr[i].F-1] < v[arr[i].S-1])
{
curr++;
id+=(1LL<<i);
}
// cout<<curr<<','<<id<<' ';
if(s.find(id)==s.end())
{
s.insert(id);
ans+=curr;
}
} while (next_permutation(all(v)));
cout<<ans;
}
