1 #include<cstring>
 2 #include<cstdio>
 3 #define R register
 4 #define MAXN 110
 5 #define mod 1000000007
 6 #define abs(_a) ((_a)<0?-(_a):_a)
 7 using namespace std;
 8 int n,m,cnt = 0;
 9 struct BLOCK{
10     int a,b;
11 }B[MAXN];
12 int from[MAXN],col[MAXN];
13 bool G[MAXN][MAXN],flag;
14 int sks,slr;
15 int dp[MAXN][MAXN];
16 void dfs(int u,int g)
17 {
18     from[u] = cnt;
19     col[u] = g;
20     g ? ++sks : ++slr;
21     for(R int i = 1; i <= n; i++)
22     {
23         if(flag) return;
24         if(col[i] == g && !G[i][u] && from[i] && i != u) //存在奇环
25         {
26             puts("0");
27             flag = 1;
28             return;
29         }
30         if(from[i]) continue;
31         if(!G[i][u])dfs(i,g^1);
32     }
33 }
34 int main()
35 {
36     memset(col,-1,sizeof(col));
37     scanf("%d%d",&n,&m);
38     for(R int i = 1; i <= m; i++)
39     {
40         int u,v;
41         scanf("%d%d",&u,&v);
42         G[u][v] = G[v][u] = true;
43     }
44     for(R int i = 1; i <= n; i++)
45     {
46         if(from[i]) continue;
47         ++cnt;
48         sks = slr = 0;
49         dfs(i,0);
50         if(flag) return 1 ^ 1;
51         B[cnt].a = sks;
52         B[cnt].b = slr;
53     }
54     dp[0][0] = 1;
55     for(R int i = 1; i <= cnt; i++)
56         for(R int j = 0; j <= n; j++)
57         {
58             dp[i][j] = (dp[i-1][abs(j+B[i].a-B[i].b)] + dp[i-1][abs(j-B[i].a+B[i].b)])%mod;
59         }
60     printf("%d",dp[cnt][0]);
61     return 0;
62 }