#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define MOD 1000000007
#define MOD2 998244353
#define int long long
//#define PI 3.14159265358979

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;

template < typename T >
ostream &operator<<(ostream &os, const vector< T > &A) {
	for (int i = 0; i < A.size(); i++)
		os << A[i] << " ";
	os << endl;
	return os;
}
template <>
ostream &operator<<(ostream &os, const vector< vector< int > > &A) {
	int N = A.size();
	int M;
	if (N > 0)
		M = A[0].size();
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < M; j++)
			os << A[i][j] << " ";
		os << endl;
	}
	return os;
}

typedef pair< int, int > pii;
typedef long long ll;

struct edge {
	int from, to, d, c;
	edge(int _from = 0, int _to = 0, int _d = 0, int _c = 0) {
		from = _from;
		to = _to;
		d = _d;
		c = _c;
	}
	bool operator<(const edge &rhs) const {
		return (d == rhs.d) ? (c < rhs.c) : (d < rhs.d);
	}
};
struct aabb {
	int x1, y1, x2, y2;
	aabb(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {}
};

typedef vector< edge > edges;
typedef vector< edges > graph;
struct flow {
	int to, cap, rev, cost;
	flow(int to = 0, int cap = 0, int rev = 0, int cost = 0) : to(to), cap(cap), rev(rev), cost(cost) {}
};
typedef vector< vector< flow > > flows;

const int di[4] = {0, -1, 0, 1};
const int dj[4] = {-1, 0, 1, 0};
const int ci[5] = {0, 0, -1, 0, 1};
const int cj[5] = {0, -1, 0, 1, 0};
const ll LINF = LLONG_MAX / 2;
const int INF = INT_MAX / 2;
const double PI = acos(-1);

int pow2(int n) { return 1 << n; }
template < typename T, typename U >
bool chmin(T &x, const U &y) {
	if (x > y) {
		x = y;
		return true;
	}
	return false;
}
template < typename T, typename U >
bool chmax(T &x, const U &y) {
	if (x < y) {
		x = y;
		return true;
	}
	return false;
}

struct initializer {
	initializer() {
		cout << fixed << setprecision(11);
	}
};
initializer _____;

int N, M, K, T, Q, H, W;
void dfs(graph &G, vector< bool > &done, vector< int > &o, int x, int p) {
	rep(i, G[x].size()) {
		edge e = G[x][i];
		if (e.d != 0 || e.to == p)
			continue;
		if (done[e.to]) {
			G[x][i].d = 1;
			o[x]++;
			G[e.to][e.c].d = -1;
		} else {
			done[e.to] = true;
			dfs(G, done, o, e.to, x);
		}
	}
}
void dfs2(graph &G, vector< int > &o, int x, int p, int j) {
	rep(i, G[x].size()) {
		edge e = G[x][i];
		if (e.to == p || e.d != 0)
			continue;
		dfs2(G, o, e.to, x, i);
	}
	if (p == -1)
		return;
	if (o[x] % 2 == 0) {
		G[p][j].d = 1;
		o[p]++;
		G[x][G[p][j].c].d = -1;
	} else {
		G[p][j].d = -1;
		G[x][G[p][j].c].d = 1;
		o[x]++;
	}
}
signed main() {
	cin >> N >> M;
	graph G(N);
	rep(i, M) {
		int A, B;
		cin >> A >> B;
		--A;
		--B;
		G[A].push_back(edge(A, B, 0, G[B].size()));
		G[B].push_back(edge(B, A, 0, G[A].size() - 1));
	}
	if (M & 1) {
		cout << -1 << endl;
		return 0;
	}
	vector< bool > done(N, false);
	vector< int > o(N, 0);
	done[0] = true;
	dfs(G, done, o, 0, -1);
	//cout << o << endl;
	dfs2(G, o, 0, -1, -1);
	//cout << o << endl;
	rep(i, N) rep(j, G[i].size()) {
		edge e = G[i][j];
		if (e.d == 1) {
			cout << e.from + 1 << " " << e.to + 1 << endl;
		}
	}
	return 0;
}

Measured memory_bytes: 21760