#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
int N, M;
const int MOD = 998244353;
struct Edge{
int sides[2];
int dir= 0;
Edge(){};
Edge(int a, int b){
sides[0] = a;
sides[1] =b;
}
int dest(){
return sides[dir];
}
int origin(){
return sides[dir^1];
}
};
vector<vector<int>> adj;
vector<Edge> edges;
vector<int> ch(int i){
vector<int> res;
for(auto eid : adj[i]){
Edge edge= edges[eid];
if(i == edge.origin()){
res.push_back(edge.dest());
}
}
return res;
}
bool is_DAG(int mask){
for(int i = 0; i<M; i++){
edges[i].dir = (mask>>i)& 1;
}
vector<int> free;
vector<int> in_deg(N);
for(int i = 0; i<N; i++){
for(auto c: ch(i)){
in_deg[c]++;
}
}
for(int i = 0; i<N; i++){
if(in_deg[i]==0){
free.push_back(i);
}
}
while(free.size()>0){
int i = free.back();
free.pop_back();
for(auto c: ch(i)){
in_deg[c]--;
if(in_deg[c]==0){
free.push_back(c);
}
}
}
for(int i = 0; i<N; i++){
if(in_deg[i]>0){
return false;
}
}
return true;
}
int get_mask(vector<int>& order){
int res = 0;
for(int i = 0; i<M; i++){
Edge e= edges[i];
if(order[e.sides[0]]>order[e.sides[1]]){
res |= (1LL<<i);
}
}
return res;
}
unordered_set<int> get_valid_masks(){
vector<int> order;
for(int i = 0; i<N; i++){
order.push_back(i);
}
bool ok = true;
unordered_set<int> masks;
while(ok){
masks.insert(get_mask(order));
ok = next_permutation(order.begin(), order.end());
}
return masks;
}
int count_bits(int v){
if(v==0){
return 0;
}
return (v&1) + count_bits((v>>1));
}
signed main(){
cin.tie(NULL);
ios_base::sync_with_stdio(false);
cin>>N>>M;
adj.resize(N);
for(int i = 0; i<M; i++){
int a, b;
cin>>a>>b;
a--;b--;
edges.push_back(Edge(a, b));
adj[a].push_back(i);
adj[b].push_back(i);
}
int RES =0;
for(auto mask: get_valid_masks()){
//cout<<bitset<3>(mask)<<endl;
RES = (RES + count_bits(mask));
}
cout<<RES<<endl;
}
