// #define DEBUGGING
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()

template <typename T> using V = vector<T>;
template <typename T> using VV = V<V<T>>;
using ll = int64_t;
using ull = uint64_t;
using PLL = pair<ll, ll>;

template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return max(low, min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { t = clamp(t, low, high); }

namespace init__ {

struct InitIO {
    InitIO() {
        cin.tie(nullptr);
        ios_base::sync_with_stdio(false);
        cout << fixed << setprecision(30);
    }
} init_io;

}

#ifdef DEBUGGING
// #include "../debug/debug.cpp"
#include "../../debug/debug.cpp"
#else
#define DEBUG(...) 0
#define DEBUG_SEPARATOR_LINE 0
#endif

template <typename T>
T make_v(T init) { return init; }

template <typename T, typename... Tail>
auto make_v(T init, size_t s, Tail... tail) {
#define rec make_v(init, tail...)
    return V<decltype(rec)>(s, rec);
#undef rec
}

struct UnionFind {
    V<ll> rank;
    V<ll> parent;

    UnionFind(ll N) : rank(N, 0), parent(N) {
        iota(parent.begin(), parent.end(), 0ll);
    }

    ll find(ll child) {
        return (child == parent[child] ? child : parent[child] = find(parent[child]));
    }

    void unit(ll x, ll y) {
        ll px = find(x);
        ll py = find(y);
        if(px == py) {
            return;
        }
        if(rank[px] < rank[py]) {
            swap(px, py);
        }
        parent[py] = px;
        rank[px] += (rank[px] == rank[py]);
    }

    bool same(ll x, ll y) {
        return (find(x) == find(y));
    }
};

V<set<ll>> edges;
VV<ll> tree_edges;
V<ll> tree_parents;
V<ll> depth;
using PQ = priority_queue<PLL, V<PLL>, less<PLL>>;

void dfs(ll now, ll pre, PQ &que, ll d = 0) {
    bool leaf = true;
    depth[now] = d;
    for(ll nxt : tree_edges[now]) {
        if(nxt == pre) continue;
        leaf = false;
        dfs(nxt, now, que, d + 1);
    }
    tree_parents[now] = pre;
    if(leaf) que.emplace(depth[now], now);
}

int main() {
    ll N, M;
    cin >> N >> M;
    edges.resize(N);
    tree_edges.resize(N);
    tree_parents.resize(N);
    V<PLL> all_edges(M);
    depth.resize(N);

    set<PLL> edges_st;

    for(ll i = 0; i < M; i++) {
        ll a, b;
        cin >> a >> b;
        a--; b--;
        if(a > b) swap(a, b);
        if(edges_st.find(PLL(a, b)) != edges_st.end()) assert(false);
        edges_st.emplace(a, b);
        edges[a].insert(b);
        edges[b].insert(a);
        all_edges[i] = PLL(a, b);
    }


    UnionFind uf(N);
    for(auto &&ele : all_edges) {
        ll a, b;
        tie(a, b) = ele;
        if(uf.same(a, b)) continue;
        DEBUG(make_tuple(a,b));
        tree_edges[a].push_back(b);
        tree_edges[b].push_back(a);
        uf.unit(a, b);
    }

    PQ leaves;
    dfs(0, -1, leaves);

    V<ll> cnt_in(N);

    set<PLL> ans;
    auto update_ans = [&](ll from, ll to) {
        DEBUG(PLL(from, to));
        PLL e(from, to), re(to, from);
        cnt_in[from]++;
        ans.emplace(from + 1, to + 1);
    };

    V<bool> visited(N);
    while(leaves.size()) {
        ll now = leaves.top().second;
        leaves.pop();
        ll par = tree_parents[now];
        visited[now] = true;

        for(auto &&ele : edges[now]) {
            if(ele == par) continue;
            update_ans(now, ele);
            edges[ele].erase(now);
        }

        if(now == 0) {
            assert(leaves.size() == 0);
            break;
        }

        if(cnt_in[now] % 2 == 0) update_ans(par, now);
        else update_ans(now, par);
        edges[par].erase(now);

        if(!visited[par]) {
            leaves.emplace(depth[par], par);
            visited[par] = true;
        }
    }

    DEBUG(cnt_in);
    assert(ans.size() == M);
    if(cnt_in[0] % 2 == 0) {
        for(auto &&ele : ans) cout << ele.first << ' ' << ele.second << endl;
    } else {
        cout << -1 << endl;
    }
    return 0;
}


Measured memory_bytes: 44288