#include <fstream>
#include <vector>
#include <cstring>

using namespace std;

vector< int > L[1005];
vector< int >::iterator it;

const int INF = 1000000000;

int muchii[10005][2],C[1005][1005],F[1005][1005],q[1005],sol[10005],T[1005],verif[10005];

bool viz[1005],vizn[1005];

int n,m,i,p,u,x,y,z,Min,k,nod;

inline int minim(int a, int b) {
    return a<b ? a : b;
}

bool BFS() {
    p=u=1;
    memset(viz,0,n+1);
    q[1]=1;
    viz[1]=1;
    while(p<=u) {
        if(q[p]==n) {
            p++;
            continue;
        }
        nod=q[p];
        for(it=L[nod].begin();it!=L[nod].end();it++) {
            if(viz[*it] || C[nod][*it]==F[nod][*it])
                continue;
            u++;
            q[u]=*it;
            viz[*it]=1;
            T[*it]=nod;
        }
        p++;
    }
    return viz[n];
}

int main() {
    ifstream f("critice.in");
    ofstream g("critice.out");
    f>>n>>m;
    for(i=1;i<=m;i++) {
        f>>x>>y>>z;
        muchii[i][0]=x;
        muchii[i][1]=y;
        C[x][y]=z;
        C[y][x]=z;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    while( BFS() ) {
        for(it=L[n].begin();it!=L[n].end();it++) {
            if(!viz[*it] || C[*it][n]==F[*it][n])
                continue;
            T[n]=*it;
            Min=INF;
            for(i=n;i!=1;i=T[i])
                Min=minim(Min,C[T[i]][i]-F[T[i]][i]);
            if(Min==0)
                continue;
            for(i=n;i!=1;i=T[i]) {
                F[T[i]][i]+=Min;
                F[i][T[i]]-=Min;
            }
        }
    }
    p=u=1;
    memset(vizn,0,n+1);
    q[1]=n;
    vizn[n]=1;
    while(p<=u) {
        nod=q[p];
        for(it=L[nod].begin();it!=L[nod].end();it++) {
            if(vizn[*it] || C[nod][*it]==-F[nod][*it])
                continue;
            u++;
            q[u]=*it;
            vizn[*it]=1;
            T[*it]=nod;
        }
        p++;
    }
    for(i=1;i<=m;i++)
        if((viz[muchii[i][0]] && vizn[muchii[i][1]]) || (viz[muchii[i][1]] && vizn[muchii[i][0]]))
            sol[++k]=i;
    g<<k<<"\n";
    for(i=1;i<=k;i++)
        g<<sol[i]<<"\n";
    return 0;
}