//#pragma GCC optimize ("-O3","unroll-loops")
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<time.h>
#include <random>

using namespace std;

#define REP(i, n) for(int i = 0;i < n;++i)
#define REPR(i, n) for(int i = n-1;i >= 0;--i)
#define FOR(i, m, n) for(int i = m;i < n;++i)
#define FORR(i, m, n) for(int i = m-1;i >= n;--i)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define REVERSE(v,n) reverse(v,v+n);
#define VREVERSE(v) reverse(v.begin(), v.end())
#define ll long long
#define pb(a) push_back
#define print(x) cout<<(x)<<'\n'
#define pe(x) cout<<(x)<<" "
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define lb(v,n) lower_bound(v.begin(), v.end(), n)
#define ub(v,n) upper_bound(v.begin(), v.end(), n)
#define int long long
#define all(x) (x).begin(), (x).end()
#define print_space(v) REP(i,v.size())cout << v[i] << ((i == v.size() - 1) ? "\n" : " ")

template<typename T1, typename T2> inline void chmin(T1 & a, T2 b) { if (a > b) a = b; }
template<typename T1, typename T2> inline void chmax(T1& a, T2 b) { if (a < b) a = b; }
typedef pair<int, int>P;
const int MOD = 998244353; const int MAX = 200020;
const double pi = acos(-1); const double EPS = 1e-12;
const ll INF = 1e18;
int siz[MAX];//錬結成分のサイズ
int par[MAX];//親
int Rank[MAX];//木の深さ

//n要素で初期化
void init(int n) {
	REP(i, n) {
		par[i] = i;
		Rank[i] = 0;
		siz[i] = 1;
	}
}

//木の根を求める
int find(int x) {
	if (par[x] == x) {
		return x;
	}
	else {
		return par[x] = find(par[x]);//経路圧縮(根に直接つなぎなおす)もしつつ
	}
}

//xとyの属する集合を併合
void unite(int x, int y) {
	x = find(x);
	y = find(y);
	if (x == y)return;
	//低いほうを高いほうにつなげる(効率化)
	if (Rank[x] < Rank[y]) {
		par[x] = y;
		siz[x] += siz[y];
		siz[y] = siz[x];
	}
	else {
		siz[y] += siz[x];
		siz[x] = siz[y];
		par[y] = x;
		if (Rank[x] == Rank[y])Rank[x]++;
	}
}

//xとyが同じ集合に属するか否か
bool same(int x, int y) {
	return find(x) == find(y);
}
vector<P>ans;
vector<int>G[100010];
int score[100010];
set<P>edges;
void dfs(int n, int pre) {
	for (auto nxt : G[n]) {
		if (pre == nxt)continue;
		dfs(nxt, n);
	}
	if (n != 0) {
		if (!(score[n] & 1)) {
			score[pre] ^= 1;
			ans.push_back({ pre,n });
		}
		else {
			ans.push_back({ n,pre });
		}
	}
}

void solve() {
	int N, M; cin >> N >> M;
	REP(i, M) {
		int u, v; cin >> u >> v;
		u--, v--;
		edges.insert({ u,v });
	}
	if (M & 1) { print(-1); return; }
	init(N+1);
	auto itr = edges.begin();
	//while (itr != edges.end()) {
	for(auto p:edges){
		//int u = itr->first, v = itr->second;
		int u = p.first, v = p.second;
		if (same(u, v)) { score[u] ^= 1; itr++; ans.push_back({ u,v }); }
		else {
			G[u].push_back(v);
			G[v].push_back(u);
			unite(u, v);
			itr++;
		}
	}
	dfs(0, 0);
	if (score[0] & 1) {
		print(-1); return;
	}
	else {
		REP(i, M) {
			pe(ans[i].first+1); print(ans[i].second+1);
		}
	}
}


signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	solve();
}




Measured memory_bytes: 24816