#include <cstdio>
#include <queue>
#include <stack>
#include <vector>
#include <algorithm>

#define vv 1001
#define minim(x,y) ((x)<(y)?(x):(y))


using namespace std;

int c[vv][vv],f[vv][vv],v[vv],d[vv][vv];
int n,m;
queue <int> q,w,aa;
stack <int> s;
vector <int> l;

void citire()
{
    freopen("critice.in","r",stdin);
    scanf("%d%d", &n, &m);
    int x,y;
    for (int i=1; i<=m; i++)
    {
        scanf("%d%d", &x, &y);
        scanf("%d", &c[x][y]);
        c[y][x]=c[x][y];
        d[x][y]=d[y][x]=i;
    }
}

int bf(int st,int w)
{
    q.push(st);
    memset(v,0,sizeof(v));
    v[1]=st;
    int e;
    while (!q.empty())
    {
        e=q.front();
        q.pop();
        for (int i=1; i<=n; i++)
            if (f[e][i]<c[e][i] && !v[i])
            {
                v[i]=e;
                q.push(i);
            }
    }
    return v[w];
}

void flux()
{
    int a=20000;
    int nod=n;
    while (nod!=1)
    {
        a=minim(a,c[nod][v[nod]]-f[nod][v[nod]]);
        s.push(nod);
        nod=v[nod];
    }
    nod=1;
    while (!s.empty())
    {
        f[nod][s.top()]+=a;
        f[s.top()][nod]=f[nod][s.top()];
        if (f[nod][s.top()]==c[nod][s.top()])
        {
            aa.push(nod);
            int t=s.top();
            w.push(t);
            c[nod][s.top()]=c[s.top()][nod]=0;
        }
        nod=s.top();
        s.pop();
    }
}

void critice()
{
    while (!w.empty())
    {
        int p=aa.front();
        int o=w.front();
        aa.pop();
        w.pop();
        if (p==1 && bf(o,n))
            l.push_back(d[p][o]);
        else
        if (o==1 && bf(p,n))
            l.push_back(d[p][o]);
        else
        if (p==n && bf(1,o))
            l.push_back(d[p][o]);
        else
        if (o==n && bf(1,p))
            l.push_back(d[p][o]);
        else
        if ((bf(1,p) && bf(o,n)) || (bf(1,o) && bf(p,n)))
            l.push_back(d[p][o]);
    }
    sort(l.begin(),l.end());
    printf("%d\n", l.size());
    for (vector <int> ::iterator it=l.begin(); it!=l.end(); it++)
        printf("%d\n", *it);
}

int main()
{
    citire();
    while (bf(1,n))
        flux();
    freopen("critice.out","w",stdout);
    critice();
    return 0;
}