#include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

 #define LEN 200000

 typedef struct node node_t;

 typedef struct node

 {

     int n;

     node_t *next;

 }node;

 int vis[LEN];    //记录节点是否访问

 int walk[LEN];    //记录访问的路径

 node *e[LEN];    //邻接表 

 int n,m,res;

 void add_edge(int x,int y)

 {

     node *p;

     p = (node *)malloc(sizeof(node));

     p->n = y;

     p->next = e[x];

     e[x] = p;

     return ;

 }

 void init()

 {

     int i,x,y;

     scanf("%d%d",&n,&m);//节点数，线路条数 

     memset(vis,,sizeof(vis));

     memset(walk,,sizeof(walk));

     for (i= ; i<=n ; i++)

         e[i] = NULL;

     for (i= ; i<m ; i++)

     {

         scanf("%d%d",&x,&y);

         add_edge(x,y);//双向图

         add_edge(y,x);

     }

     return ;

 }

 void DP(int cur,int step)

 {

     int i;

     node *p = e[cur];

     walk[step] = cur;    //记录路径上的节点 

     if (step>)    //转发数必须大于两次

     {

         res ++;

         return ;

     }

     while (p!=NULL)

     {

         if (vis[p->n]==)//下一节点可访问

         {

             vis[p->n] = ;

             DP(p->n,step+);

             vis[p->n] = ;

         }

         if (step>= && p->n==walk[])

         {

             DP(p->n,step+);//源地址与目的地址相同

         }

         p = p->next;

     }

     return ;

 }

 int main(void)

 {

     int i;

     init();    //初始化

     res = ;

     for (i= ; i<=n ; i++)//遍历所有节点

     {

         vis[i] = ;

         DP(i,);

         vis[i] = ;

     }

     printf("%d",res);

     return ;

 }