#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>
#include <cassert>


using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<n;++i)
#define FOR(i, a, b) for(int i=a;i<b;++i)
#define RREP(i, n) for(int i=n-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=b-1;i>=a;--i)

#define all(x) begin(x),end(x)
#define dump(x) cerr<<#x<<" = "<<(x)<<endl
#define debug(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}


template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> p) {
    os << p.first << ":" << p.second;
    return os;
}

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

template<class T1, class T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
    os << "[";
    for (auto it = mp.begin(); it != mp.end(); ++it) {
        if (it != mp.begin()) {
            os << ", ";
        }
        os << *it;
    }
    return os << "]";
}

// edit

int N, M;
vector<vector<int>> G;
vector<bool> visited;
vector<bool> parity;
//vector<P> edges;
set<P> edges;

bool insert(int v, int w) {
    if (!edges.count(P(v, w)) && !edges.count(P(w, v))) {
        edges.insert(P(v, w));
        return true;
    }

    return false;
}

void dfs(int v, int p = -1) {
    visited[v] = true;

    for (auto c : G[v]) {
        if (c == p) continue;

        if (visited[c]) {
            // add edge (c, v)
//            edges.emplace_back(c, v);
//            edges.insert(P(c, v));
            if (insert(c, v)) {
                parity[c] = !parity[c];
            }
        } else {
            dfs(c, v);
        }
    }

    if (p == -1) return;

    if (parity[v]) {
        // add edge (v, p)
        if (insert(v, p)) {
            parity[v] = !parity[v];
        }
//        edges.insert(P(v, p));
    } else {
        // add edge (p, v)
        if (insert(p, v)) {
            parity[p] = !parity[p];
        }
//        edges.insert(P(p, v));
    }
}

void solve() {
    cin >> N >> M;
    G.resize(N);
    visited.resize(N);
    parity.resize(N);

    REP(i, M) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        G[a].push_back(b);
        G[b].push_back(a);
    }

    if (M % 2) {
        cout << -1 << endl;
        return;
    }

    dfs(0);
    for (auto e : edges) {
        cout << (e.first + 1) << " " << (e.second + 1) << endl;
    }


}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
//    std::ifstream in("input.txt");
//    std::cin.rdbuf(in.rdbuf());

    solve();


    return 0;
}


Measured memory_bytes: 19456