#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#  include <intrin.h>
#  define __builtin_popcount __popcnt
#endif

#define _USE_MATH_DEFINES

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <unordered_map>
#include <stack>
#include <list>
#include <math.h>
#include <bitset>
#include <iterator>
#include <map>
#include <iomanip>
#include <functional>
#include <string>
#include <algorithm>
#include <queue>
#include <random>
#include <numeric>
#include <set>
#include <cassert>
#include <cmath>
#include <cinttypes>

using namespace std;

template<class T> ostream& operator<<(ostream& os, const vector<T>& v) { for (auto i = begin(v); i != end(v); i++) os << *i << (i == end(v) - 1 ? "" : " "); return os; }
template<class T> istream& operator>>(istream& is, vector<T>& v) { for (auto i = begin(v); i != end(v); i++) is >> *i; return is;}
struct fast_io {
	fast_io& operator>> (int& target) { scanf("%" PRId32, &target);  return *this; }
	fast_io& operator>> (unsigned int& target) { scanf("%" PRIu32, &target);  return *this; }
	fast_io& operator>> (long long& target) { scanf("%" PRId64, &target);  return *this; }
	fast_io& operator>> (unsigned long long& target) { scanf("%" PRIu64, &target);  return *this; }
	template<typename T> fast_io& operator>> (vector<T>& target) { for (auto& value : target) { *this >> value; } return *this; }
	fast_io& operator<< (const int value) { printf("%" PRId32, value); return *this; }
	fast_io& operator<< (const unsigned int value) { printf("%" PRIu32, value); return *this; }
	fast_io& operator<< (const long long value) { printf("%" PRId64, value); return *this; }
	fast_io& operator<< (const unsigned long long value) { printf("%" PRIu64, value); return *this; }
	fast_io& operator<< (const string& value) { printf("%s", value.c_str()); return *this; }
	template<typename T> fast_io& operator<< (const vector<T>& target) { for (auto& value : target) { *this << value << " "; } return *this; }
}; fast_io fio;

template<class ForwardIt, class UnaryPredicate>
ForwardIt first_true(ForwardIt first, ForwardIt last, UnaryPredicate predicate){
	ForwardIt it;
	typename std::iterator_traits<ForwardIt>::difference_type count, step; count = std::distance(first, last);
	while (count > 0) {
		it = first;	step = count / 2;
		std::advance(it, step);
		if (!predicate(*it)) { first = ++it; count -= step + 1; }
		else count = step;
	}
	return first;
}

#define MOD 1000000007
#define pii pair<int,int>
#define pll pair<long long, long long>
#define all(x) (x).begin(), (x).end()
#define sort_all(x) sort(all(x))
#define make_unique(x) (x).erase(unique(all(x)), (x).end())

bool visited[200000];
set<pii> inverted;

int dfs(int v, vector<vector<int>> &G, vector<int> &odd)
{
	if (visited[v])
		return 0;
	visited[v] = true;

	int total = 0;
	for (int u : G[v])
	{
		int x = dfs(u, G, odd);
		if (x % 2 == 1)
			inverted.insert({ v,u });
		total += x;
	}
	total += odd[v];
	return total;
}

int main() {

#if defined(_DEBUG)
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	int n, m;
	fio >> n >> m;

	vector<vector<int>> G(n);
	vector<int> odd(n, 0);
	vector<pii> edges;
	for (int i = 0; i < m; i++)
	{
		int a, b;
		fio >> a >> b;
		a--, b--;
		G[a].push_back(b);
		G[b].push_back(a);
		edges.push_back({ a,b });
		odd[a] = !odd[a];
	}

	int cnt_odd = 0, odd_id=0;
	for (int i = 0; i < n;i++) {
		cnt_odd += odd[i];
		if (odd[i]) odd_id = odd[i];
	}
	if (cnt_odd % 2 == 1)
		fio << -1;
	else if (cnt_odd == 0)
	{
		for (auto x : edges)
		{
			fio << x.first + 1 << " " << x.second + 1 << "\n";
		}
	}
	else
	{
		dfs(odd_id, G, odd);
		for (auto x : edges)
		{
			if (inverted.find({ x.first,x.second }) != inverted.end()
				|| inverted.find({ x.second,x.first }) != inverted.end())
				swap(x.first, x.second);
			fio << x.first + 1 << " " << x.second + 1 << "\n";
		}
	}

	return 0;
}

Measured memory_bytes: 21492