#include <bits/stdc++.h>
using namespace std;
using LL = long long;

#define fs first
#define sc second

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }


// std::vector Declaration
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

// std::vector Initialization
template<typename T>
void fill_all(T& arr, const T& v) { arr = v; }
template<typename T, typename U>
void fill_all(T& arr, const U& v) { for (auto& i : arr) fill_all(i, v); }

// std::vector Debug
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v ) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::pair Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << " " << p.second << ")";
    return os;
}

// std::set Debug
template<typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::multiset Debug
template<typename T>
ostream& operator<<(ostream& os, const multiset<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::map Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
    os << "{";
    bool a = 1;
    for (auto e : mp) {
        os << (a ? "" : " ");
        os << e.first << ":" << e.second;
        a = 0;
    }
    os << "}";
    return os;
}

// std::tuple Debug
template<int N, class Tuple>
void out(ostream& os, const Tuple& t){}
template<int N, class Tuple, class H, class ...Ts>
void out(ostream& os, const Tuple& t) {
    if (N) os << " ";
    os << get<N>(t);
    out<N+1,Tuple,Ts...>(os, t);
}
template<class ...Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
    os << "(";
    out<0,tuple<Ts...>,Ts...>(os, t);
    os << ")";
    return os;
}

// Debug
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl


struct edge { int to, rev, direction; };
ostream& operator<<(ostream& os, const edge& e) {
    os << "(" << e.to << ", " << e.direction << ")";
    return os;
}

const LL LINF = 1LL<<60;
const int IINF = 1<<30;
const LL MOD = 1e9+7;

int dfs(auto& G, auto& vis, int v, int p) {
    vis[v] = true;
    int sum = 0;
    for (auto &e : G[v]) {
        if (e.to == p) continue;
        if (!vis[e.to]) {
            e.direction = dfs(G, vis, e.to, v);
            G[e.to][e.rev].direction = e.direction ^ 1;
        }
        sum ^= e.direction;
    }
    return sum ^ 1;
}

int main()
{
    int n, m; cin >> n >> m;
    vector<vector<edge>> G(n);
    for (int i = 0; i < m; ++i) {
        int a, b; cin >> a >> b; --a; --b;
        G[a].push_back(edge{ b,(int)G[b].size(),1 });
        G[b].push_back(edge{ a,(int)G[a].size()-1,0 });
    }

    if (m % 2 == 1) {
        cout << -1 << endl;
        return 0;
    }

    vector<bool> vis(n,false);
    dfs(G, vis, 0, -1);

    for (int v = 0; v < n; ++v) {
        for (auto e : G[v]) {
            if (e.to < v) continue;
            if (e.direction) {
                printf("%d %d\n", v+1, e.to+1);
            } else {
                printf("%d %d\n", e.to+1, v+1);
            }
        }
    }

    return 0;
}


Measured memory_bytes: 14720