#include<iostream>

using namespace std;

const int N=11;
int ship[N][N];
int path[N];
int n,m,cnt;
bool state[N];
bool flag=0;

void dfs(int u)
{
    if(u==n)
    {
        path[u]=1;
        for(int i=0;i<n;i++)
        if(ship[path[i+1]][path[i]]||ship[path[i]][path[i+1]])return;
        cnt++;
        return;
    }

    for(int i=2;i<=n;i++)
    {
        if(!state[i])
        {
            state[i]=1;
            path[u]=i;
            dfs(u+1);
            state[i]=0;
        }
    }
}

int main()
{
    cin>>n>>m;

    int x,y;
    while(m--)
    {
        cin>>x>>y;
        ship[x][y]=ship[y][x]=1;
    }

    path[0]=1;

    dfs(1);
    cout<<cnt<<endl;

    return 0;
}