/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

#include <iostream>
#include <fstream>

#ifndef  _TB
#define _TB

#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define RFOR(i, b, a) for(int i = b - 1; i >= a; --i)
#define REP(i, N) FOR(i, 0, N)
#define RREP(i, N) RFOR(i, N, 0)

#define MIN(A, B) ((A) < (B) ? (A) : (B))
#define MAX(A, B) ((A) > (B) ? (A) : (B))
#define ABS(A) ((A) < 0 ? (-(A)) : (A))
#define ALL(V) V.begin(), V.end()
#define SIZE(V) (int)V.size()
#define pb push_back
#define mp make_pair
#define EPS 1e-7
#define Pi 3.14159265358979
#define FILL(a,v) memset(a,v,sizeof(a))

using namespace std;

typedef long long Long;
typedef unsigned long long ULong;
typedef unsigned int Uint;
typedef unsigned char Uchar;
typedef vector <int> VI;
typedef pair <int, int> PII;

#define X first
#define Y second

typedef std::pair<int,int> pii; typedef long long ll; typedef unsigned long long ull; typedef unsigned int ui; typedef pair<ui,ui> puu;

template <typename T, typename U> std::istream&operator>>(std::istream&i, pair<T,U>&p) {i >> p.X >> p.Y; return i;}
template<typename T>std::istream&operator>>(std::istream&i,vector<T>&t) {for(auto&v:t){i>>v;}return i;}
template <typename T, typename U> std::ostream&operator<<(std::ostream&o, const pair<T,U>&p) {o << p.X << ' ' << p.Y; return o;}
template<typename T>std::ostream&operator<<(std::ostream&o,const vector<T>&t) {if(t.empty())o<<'\n';for(size_t i=0;i<t.size();++i){o<<t[i]<<" \n"[i == t.size()-1];}return o;}
template<typename T> using minheap = priority_queue<T, vector<T>, greater<T>>;
template<typename T> using maxheap = priority_queue<T, vector<T>, less<T>>;
template <typename T> bool in(T a, T b, T c) { return a <= b && b < c; }
ui logceil(int x) { return (ui)(8*sizeof(int)-__builtin_clz(x)); }

namespace std { template<typename T,typename U>struct hash<pair<T,U>>{hash<T>t;hash<U>u;size_t operator()(const pair<T,U>&p)const{return t(p.x)^(u(p.y)<<7);}}; }
template<typename T> T gcd(T a,T b) { if (a<b) swap(a,b); return b?gcd(b,a%b):a; }

template<typename T>class vector2:public vector<vector<T>>{public:vector2(){} vector2(size_t a,size_t b,T t=T()):vector<vector<T>>(a,vector<T>(b,t)){}};
template<typename T>class vector3:public vector<vector2<T>>{public:vector3(){} vector3(size_t a,size_t b,size_t c,T t=T()):vector<vector2<T>>(a,vector2<T>(b,c,t)){}};
template<typename T>class vector4:public vector<vector3<T>>{public:vector4(){} vector4(size_t a,size_t b,size_t c,size_t d,T t=T()):vector<vector3<T>>(a,vector3<T>(b,c,d,t)){}};
template<typename T>class vector5:public vector<vector4<T>>{public:vector5(){} vector5(size_t a,size_t b,size_t c,size_t d,size_t e,T t=T()):vector<vector4<T>>(a,vector4<T>(b,c,d,e,t)){}};

void fastIO(){ios::sync_with_stdio(false); }

template<typename T, typename... Args>
T max(T t, Args... args){ return max(max<T>(args...), t) ;}

template<typename T, typename... Args>
T min(T t, Args... args){ return min(min<T>(args...), t) ;}

#endif

vector<PII> e;


vector<VI> g;


const int MAXN = 100000;

int d[MAXN];

void bfs(int v) {
    d[v] = 0;
    queue<int> q;
    q.push(v);

    while (!q.empty()) {
        int t = q.front();  q.pop();
        int cd = d[t];
        for(auto nv: g[t])
            if (d[nv] == -1) {
                d[nv] = cd+1;
                q.push(nv);
            }
    }
}

int p[MAXN];

vector<PII> ans;

multiset<PII> pp;


void addV(int v) {
    if (p[v] > 1)
        pp.insert({d[v], v});
}

void rmV(int v) {
    auto it = pp.find({d[v], v});
    if (it != pp.end())
        pp.erase(it);
}

void rmE(int v) {
    if (p[v] > 2)
        --p[v];
    else {
        rmV(v);
        --p[v];
        addV(v);
    }
}

map<int, set<int> > was;

void addE(int a, int b) {
    was[a].insert(b);
    was[b].insert(a);
    ans.pb({a,b});
    rmE(a);
    rmE(b);
}




class BEvenDegrees {
public:
    void solve(std::istream& in, std::ostream& out) {
        fastIO();

        int n,m;
        in >> n >> m;
        e.resize(m);
        g.clear();
        g.resize(n);
        FILL(p, 0);
        REP(i,m) {
            in >> e[i];
            e[i].X --;
            e[i].Y --;
            g[e[i].X].pb(e[i].Y);
            g[e[i].Y].pb(e[i].X);
            p[e[i].X] ++;
            p[e[i].Y] ++;
        }

        if (m%2 == 1) {
            out << -1;
            return;
        }

        FILL(d, -1);

        bfs(0);


        pp.clear();

        REP(i, n) {
            addV(i);
        }

        REP(i, n) {
            sort(ALL(g[i]), [](int a, int b) {
                return d[a] < d[b];
            });
        }

        ans.clear();


        REP(i, m/2) {
            auto it = pp.rbegin();
            auto v = it->second;

            while (was[v].count(g[v].back()))
                g[v].pop_back();
            addE(v, g[v].back());

            while (was[v].count(g[v].back()))
                g[v].pop_back();
            addE(v, g[v].back());
        }

        REP(i, m) {
            out << ans[i].X +1 << " " << ans[i].Y + 1 << endl;
        }

    }
};


int main() {
	BEvenDegrees solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
	return 0;
}


Measured memory_bytes: 28020