#include <cstdio>
#include <stack>
#include <vector>

using namespace std;
#define MAXM 500005
#define MAXN 100005


struct muchie
{
    int a, b;
    bool ex;
};
struct pr
{
    int nod, id;
};

vector<int> v[MAXN], sol;
stack<pr> st;
muchie muc[MAXM];
int n, m;
void eul(int sursa);

int main()
{
    freopen("ciclueuler.in", "r", stdin);
    freopen("ciclueuler.out", "w", stdout);
    int i, a, b;
    scanf("%d%d", &n, &m);
    for(i=1; i<=m; i++)
    {
        scanf("%d%d", &a, &b);
        v[a].push_back(i);
        v[b].push_back(i);
        muc[i].a = a; muc[i].b = b; muc[i].ex = 1;
    }
    eul(muc[1].a);
    vector<int>::iterator it;
    for(it=sol.begin(); it!=sol.end() - 1; ++it)
        printf("%d ", *it);
    return 0;
}
void eul(int sursa)
{
    int tata, fiu, vec;
    vector<int>::iterator it;
    pr p;
    p.nod = sursa; p.id = 1;
    st.push(p);
    while(!st.empty())
    {
        tata = st.top().nod;
        vec = 0;
        for(it=v[tata].begin(); it!=v[tata].end(); ++it)
            if(muc[*it].ex)
                vec++;
        if(!vec)
        {
            sol.push_back(st.top().id);
            st.pop();
        }
        for(it=v[tata].begin(); it!=v[tata].end(); ++it)
        {
            if(muc[*it].ex)
            {
                if(muc[*it].a == tata)
                    fiu = muc[*it].b;
                else
                    fiu = muc[*it].a;
                muc[*it].ex = 0;
                p.nod = fiu; p.id = *it;
                st.push(p);
                break;
            }
        }
    }
}