#include <cstdio>
#include <map>
#include <set>
#include <sstream>
#include <string>
#include <iostream>
#include <utility>
#include <queue>
#include <cmath>
using namespace std;
#define forn(i,n) for(int i=0;i<(n);++i)
#define fornr(i,n) for(int i=(n)-1;i>=0;--i)
#define forv(i,v) forn(i,(int)v.size())
#define forvr(i,v) fornr(i,(int)v.size())
#define mp make_pair
#define pb push_back
#define lng long long
#define SQ(a) ((a)*(a))
#define eps 1e-8
#define VI vector<int>


bool can[1000][1000];
vector<int> grav[1000+100];
bool was[1000+100];
int s;
int a[30000];
int b[30000];

void dfs(int v)
{
    was[v]=true;
    can[s][v]=true;
    forv(i,grav[v])
    {
        if (!was[grav[v][i]])
        {
            dfs(grav[v][i]);
        }
    }
}

int val[30000];


int main(int argc, char *argv[])
{
#ifdef __qwe__
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int n, m;
    cin >> n >> m;
    forn(i,m)
    {
        int u, v;
        scanf("%d%d", &u, &v);
        --u;--v;
        grav[u].pb(v);
        a[i]=u;
        b[i]=v;
    }


    forn(i,n)
    {
        s = i;
        memset(was,0,sizeof(was));
        dfs(s);
    }

    int maxsrc=0;
    forn(i,n)
    {
        int sz=0;
        forn(j,n)
            if(can[i][j]&&can[j][i])
                ++sz;
        maxsrc=max(maxsrc,sz);
    }

    forn(i,m)
    {
        int x = a[i];
        int y = b[i];
        val[i]=0;
        forn(v,n)
        {
            if (can[x][v] && can[v][y])
            {
                ++val[i];
                continue;
            }
            if (can[y][v] && can[v][x])
            {
                ++val[i];
                continue;
            }
            if (can[y][v] && can[v][y])
            {
                ++val[i];
                continue;
            }
            if (can[x][v] && can[v][x])
            {
                ++val[i];
                continue;
            }
        }
    }




    int res = *max_element(val, val+m);
    printf("%d\n",res);
    int cnt=0;
    forn(i,m)if(val[i]==res||res==maxsrc)++cnt;
    printf("%d\n", cnt);
    forn(i,m)if(val[i]==res||res==maxsrc)printf("%d ",i+1);
    printf("\n");
    return 0;
}