#include <cstdio>
#include <cstring>
#define Nmx 102
#define INF 0x3f3f3f3f
#include <queue>
#include <vector>
#include <algorithm>
#define min(a,b) (a<b)? a : b

using namespace std;

int n,k,s,d,C[Nmx][Nmx],sfinal[Nmx*50],nrsf,prec[Nmx],viz[Nmx];
struct nod
{
    int inf;
    nod *urm;
};
nod *G[Nmx];
queue <int> Q;
vector <int> Ang[Nmx][Nmx];

void add(int x,int y)
{
    nod *aux=new nod;
    aux->inf=y;
    aux->urm=G[x];
    G[x]=aux;
}

void read()
{
    int x,y;
    scanf("%d%d",&n,&k);
    for(int i=1;i<=n;++i)
    {
        scanf("%d%d",&x,&y);
        C[x+1][y+1]++;
        C[y+1][x+1]--;
        Ang[x+1][y+1].push_back(i);
        Ang[y+1][x+1].push_back(i);
        add(x+1,y+1);
        add(y+1,x+1);
    }
}

int bfs()
{
    memset(viz,0,sizeof(viz));
    memset(prec,0,sizeof(prec));
    Q.push(0);
    viz[0]=1;
    prec[0]=-1;
    while(!Q.empty())
    {
        int x=Q.front();
        Q.pop();
        if(x!=d)
        {
            for(nod *p=G[x];p;p=p->urm)
                if(!viz[p->inf]&&C[x][p->inf]>0)
                {
                    viz[p->inf]=1;
                    prec[p->inf]=x;
                    Q.push(p->inf);
                }
        }
    }
    return viz[d];
}

void solve()
{
    s=0;d=101;
    C[0][1]=k;
    add(0,1);
    Ang[0][1].push_back(1);
    int Vmin=INF,sf=0;
    while(bfs())
    {
        for(nod *p=G[d];p;p=p->urm)
        if(C[p->inf][d]>0&&viz[p->inf])
        {
            Vmin=INF;
            prec[d]=p->inf;
            for(int j=d;prec[j]!=-1;j=prec[j])
                Vmin=min(Vmin,C[prec[j]][j]);
            if(Vmin)
            {
                for (int j=d;prec[j]!=-1;j=prec[j])
                {
                    C[prec[j]][j]-=Vmin;
                    C[j][prec[j]]+=Vmin;
                    if(prec[j]!=0)
                    {
                        for(int v=1;v<=Vmin;++v)
                        {
                            sfinal[++nrsf]=Ang[prec[j]][j].back();
                            Ang[prec[j]][j].pop_back();
                            Ang[j][prec[j]].pop_back();
                        }
                    }
                }
                sf+=Vmin;
            }
        }
    }
}

void afisare()
{
    sort(sfinal+1,sfinal+nrsf+1);
    printf("%d\n",nrsf);
    for(int i=1;i<=nrsf;++i)
        printf("%d ",sfinal[i]);
    printf("\n");
}

int main()
{
    freopen("ghizi.in","r",stdin);
    freopen("ghizi.out","w",stdout);
    read();
    solve();
    afisare();
    return 0;
}