1 #include<iostream>
 2 #include<algorithm>
 3 #include<cstring>
 4 #include<cstdio>
 5 #include<sstream>
 6 #include<vector>
 7 #include<stack>
 8 #include<queue>
 9 #include<cmath>
10 #include<map>
11 #include<cstdio>
12 #include<set>
13 using namespace std;
14 typedef long long ll;
15 typedef pair<int,int> pll;
16 const int INF = 0x3f3f3f3f;
17 const int maxn=1000+5;
18
19 int n, m;
20
21 struct Edge
22 {
23     int u, v;
24 }edge[20000+5];
25
26 int vis[maxn];
27 int mp[maxn][maxn];
28
29 vector<int> G[maxn];
30
31 void dfs(int u, int src)
32 {
33     for(int i=0;i<G[u].size();i++)
34     {
35         int v=G[u][i];
36         if(vis[v])  continue;
37         vis[v]=1;
38         mp[src][v]=1;
39         dfs(v,src);
40     }
41 }
42
43 int main()
44 {
45     freopen("input.txt","r",stdin);
46     freopen("output.txt","w",stdout);
47     //freopen("in.txt","r",stdin);
48     while(~scanf("%d%d", &n, &m))
49     {
50         for(int i=1;i<=n;i++)  G[i].clear();
51         for(int i=1;i<=m;i++)
52         {
53             scanf("%d%d",&edge[i].u, &edge[i].v);
54             G[edge[i].u].push_back(edge[i].v);
55         }
56
57         if(m==0)   {puts("1");puts("0");continue;}
58         memset(mp,0,sizeof(mp));
59         for(int i=1;i<=n;i++)
60         {
61             mp[i][i]=1;
62             memset(vis,0,sizeof(vis));
63             vis[i]=1;
64             dfs(i,i);
65         }
66
67         int now, MAX=0, cnt=0;
68         int ans[20000+5];
69         for(int i=1;i<=m;i++)
70         {
71             now=0;
72             int u=edge[i].u, v=edge[i].v;
73             for(int j=1;j<=n;j++)
74                 if(mp[u][j] && mp[j][v] || mp[v][j] && mp[j][u])  now++;
75
76             if(now>MAX)   {MAX=now;cnt=0;ans[cnt++]=i;}
77             else if(now==MAX)   ans[cnt++]=i;
78         }
79
80         printf("%d\n%d\n",MAX,cnt);
81         for(int i=0;i<cnt;i++)
82         {
83             printf("%d%c",ans[i],i==cnt-1?'\n':' ');
84         }
85     }
86     return 0;
87 }